Cooking for Geeks: Real Science, Great Hacks, and Good Food (50 page)

An emulsion is a mixture of two liquids that are immiscible — that is, unable to mix (think oil and water). Mayonnaise is the classical culinary example. Egg yolks are an emulsion, too: the fats and water are held in suspension by some of the proteins, which act as emulsifiers — compounds that can hold immiscible liquids in suspension. For more on the chemistry of emulsions, see
Colloids
in
Chapter 6
.

Some recipes rely on more than just one method of incorporating air into food. Some English muffins and Chinese pork buns, for example, use both yeast and baking powder. Waffle recipes often call for both whipped egg whites and baking powder. And some mousse recipes call for both whipped egg whites and whipped cream. If you find that a recipe isn’t turning out as light as you’d like, look to see if other methods of leavening can be added. If a recipe doesn’t rely on chemical leaveners, adding a small amount of baking powder is usually a safe bet. Or, if the recipe has eggs, try separating some of the eggs, whisking the whites, and folding the egg-white foam into the batter.

This sauce needs very few ingredients and not much in the way of equipment — a whisk, a bowl, and a stovetop — making it an easy impromptu dish even in an unfamiliar kitchen. (For more on sauces, see
Béchamel Sauce (White Sauce)
–
Grilled Fish with Bayou Sauce or Mustard Sauce
of
Chapter 3
.)

The only tricky part is preventing the eggs in this sauce from getting too hot and scrambling. If you have a gas burner, this can be done by moving the saucepan on and off a flame set to very low heat. Position yourself so that you can hold the pan with one hand while whisking with the other; you’ll need to move the pan to regulate the temperature. If you have an electric burner, use a double-boiler instead: fill a large saucepan with water and place the saucepan with the mixture inside it
.

In a saucepan, separate 3 egg yolks, saving the egg whites for some other dish. Add ¼ cup (60g) white wine and whisk to combine.

Once you’re ready to start cooking, place the pan over the flame or in the water bowl bath and whisk continuously until the egg yolks have set and you have a frothy foam, about two to three times the volume of the original. This can take 5 to 10 minutes; have patience, it’s better to go too slow than too quick.

Add 2 to 3 tablespoons (20–30g) freshly grated Parmesan cheese and whisk until thoroughly combined. Add salt and pepper to taste, and serve on top of an entrée such as fish with asparagus.

Note

This dish is easy, but it does benefit from a few practice runs. Luckily, the ingredients are cheap!

Zabaglione is the dessert equivalent of white wine and cheese sauce, made by whisking wine, sugar, and egg yolks over low heat; it’s essentially a foamy custard, but without the milk. And, like the white wine and cheese sauce, this is a great recipe to have tucked away in the back of your head.

Measure out ¼ cup (60g) Marsala wine and set aside.

In a saucepan, separate out the yolks from 3 eggs, saving the whites for something else (meringues!). Add ¼ cup (50g) sugar to the yolks and whisk to combine.

Place pan over heat, following the directions for the white wine and cheese sauce. Pour in a tablespoon of the Marsala and whisk. Continue adding the Marsala a tablespoon or so at a time, whisking for a minute between each addition. You’re looking for the egg yolks to froth up and foam; the heat will eventually set the egg yolks to make a stable foam. If you notice that the egg yolks are scrambling, quickly pour in more of the Marsala to cool the mixture down; it’s not ideal, but it’ll prevent you from having an entire dish of sweet scrambled eggs on your hands. Once the sauce begins to show soft peaks, remove from heat and serve.

Traditionally, zabaglione is served with fruit: spoon a small portion into a bowl or glass and top with fresh berries. You can also store it in the fridge for a day or two.

You’re probably wondering what soufflé is doing in the section on egg yolks, right? After all, it’s the egg whites that famously give soufflés their rise. I have a confession to make. I make my fruit-based dessert soufflés by making zabaglione. (I am so never going to win a James Beard award — the Oscar of the culinary world.)

Preheat your oven to 375°F / 190°C. Prepare a 1 quart / 1 liter soufflé bowl — which will hold enough soufflé for two to three people — by buttering the inside and then coating it with sugar (toss in a few spoonfuls, then rotate the dish back and forth to coat the side walls).

Prepare the fruit:

Fresh strawberries, raspberries, and white peaches work exceptionally well; wet fruits such as pears can work, but the water may separate while cooking, so start with berries. Rinse and dry the fruit. If using strawberries, hull them; if using peaches or other stone fruits, quarter them and remove the pit. Reserve about ½ cup — a small handful — of the fruit for placing on top of the cooked soufflé. Prepare a second handful of fruit, again about ½ cup, for cooking by slicing it into small pieces; cut strawberries into eighths and peaches into very thin slices. (Raspberries will fall apart on their own.)

Make zabaglione:

Start by making a zabaglione: whisk the 3 egg yolks with ¼ cup (50g) sugar over low heat and add ¼ cup (50g) of kirsch — cherry-flavored brandy — instead of Marsala. (Save the egg whites for whisking.) After adding the kirsch, add the fruit that’s been sliced into small pieces and stir, thoroughly mashing in the fruit. You don’t need to actually cook the egg yolks until they set; you’re just looking to stir and whisk them until you have a frothy, warm, soft foam. Set aside while preparing the egg whites.

Whisk egg whites, fold, and bake.

Whisk the egg whites to soft peak stage, adding a pinch of salt for taste. Fold the egg whites into the fruit base and transfer the mixture to the soufflé bowl. Bake in an oven until the soufflé has risen and the top is browned, about 15 to 20 minutes. Remove and place the soufflé dish on a wooden cutting board. Dust with powdered sugar, place the reserved fruit on top (slice strawberries or peaches into thin slivers), and serve at once. If you’re in informal company, it’s easiest to just set the soufflé in the center of the table and hand everyone a fork to dig in.

You can use this same technique with the white wine and cheese sauce from the previous page to make a savory soufflé.

Whipping high-quality cream increases its volume by about 80%, while whipped egg whites can expand by over 600%!

PHOTO USED BY PERMISSION OF MICHAEL CHU

Tell me a little bit about your background and how you started your blog, Cooking for Engineers (at
http://www.cookingforengineers.com
).

I am an engineer in my professional life, but I developed recipes on my own. “Developing” sounds grander than it really is. I would try out recipes and then the ones that I really liked I would keep and then tweak so that I would like them more. Friends would come over to watch TV; at the time we called them “Family Guy Nights” because we would watch the television show
Family Guy
. I would be cooking and writing down my recipes when I found something I liked. I started using Blogger, and at some point I decided I would post a recipe. I took pictures of me making salsa and then I posted that recipe. My friends liked it and so I just thought, “Oh, well, maybe this is a good way to share my recipes.” A lot of people started to come and look at the recipes, and it just kind of blew up from there.

One thing I notice about your posts is the number of variations you go through. Do you think people have a fear of trying variations when they go into the kitchen?

I think a lot of times people don’t like wasting food. There is a whole culture where wasting food is something that you don’t do. I totally agree with that, but when you’re trying to learn how to do something it’s inevitable that you will make mistakes. There will be some waste; that’s something people shouldn’t shy away from. When you’re trying a new fancy dish for the first time and you’ve never used the ingredients, you might use too much.

For example, Vietnamese fish sauce is a wonderful ingredient, but if you use a little bit too much it ruins the dish. What do you do at that point? If you eat it you might be turned off from fish sauce for the rest of your life. There is a lot of food waste that goes through my kitchen. There wouldn’t be as much if I weren’t running Cooking for Engineers, but it’s really important to experiment. It’s one thing to read a cookbook, but once in a while it’s important to deviate and try something completely new.

Time and activity chart for Simple Tiramisu.

Sometimes, these mistakes can be expensive; you might ruin your pot. Sometimes they will reveal something awesome. In some recipes, you’re told to be sure to not burn the garlic, but then if you experiment and do overcook the garlic, it becomes these little crispy bitter pieces that work really well with certain types of vegetables. People want to get it right the first time. Part of that is due to not wanting to waste the food or the money, but the other part is they haven’t gotten to the point where they’re enjoying doing it over until they get it right.

Have there been any particular recipes whose success has caught you off-guard?

Tiramisu is the recipe that launched Cooking for Engineers. I posted the tiramisu recipe, and three days later I was getting maybe 100 page views a day on that article. Enough people saw it that I got attention from Slashdot, which wrote an article about this new cooking website geared toward geeky people. Boom, I got a lot of readership. So much so that I had a little trouble keeping up with the number of people who were looking at the web pages on the little server that I was running on.

The tiramisu recipe that we have on Cooking for Engineers is a bit more simplified than many of the other tiramisu recipes. I spent a lot of time developing it. I wanted to come up with something that inexperienced cooks could do without extra steps, so I came up with a method where the cream is mixed in with the Mascarpone cheese to produce the lighter, fluffier texture. I modified the amount of ingredients so that it was well balanced. The tiramisu recipe is probably one of the best we’ve ever tasted, and very simple to make. It’s called “simple tiramisu.” After the success of the simple one I included one that was closer to what the original tiramisu was as well, to let people compare them.

Time and activity chart for Simple Tiramisu.

Cream whippers — canisters that can be filled with a liquid and then pressurized with gas (usually nitrous oxide) — are also a form of mechanical leavening. The gas dissolves into the liquid and then, upon spraying, bubbles back out of saturation, foaming up the liquid. From a structural point of view, foams created this way are entirely different from foams created by whisking: instead of a 3D mesh of surfactants holding on to the air bubbles, the air bubbles are essentially just in suspension. This is why hand-whipped cream is more stable than whipped cream from a can. For more on cream whippers, see
Cream Whippers (a.k.a. “iSi Whippers”)
in
Chapter 7
.

Compare the following two methods for making chocolate mousse. The egg-white version creates a creamy, dense mousse, while the whipped cream version creates a stiffer version.

While steam doesn’t involve mechanically trapping air as the other methods in this section do, it’s still a physical process by which air is introduced into food. Most of the recipes given so far also rely on steam generation as part of their leavening; few baked goods truly rely on only one method for providing lift. Try this popover recipe, which is a classic example of a baked good leavened by steam.

Popovers

Traditionally, these are made in specialized popover cups, which are narrow cups with a slight slope to them and that have some heft to them, giving them good heat retention. You can use muffin tins or ramekins instead.

Whisk together in a mixing bowl or blend in a blender:

Preheat both the oven and the popover cups or muffin tin at 425°F / 220°C.

Heavily grease the popover cups or muffin tins with butter: melt a few tablespoons of butter and put a teaspoon in the bottom of each cup. Fill each cup about ⅓ to ½ full with batter and bake. After 15 minutes, drop the temperature to 350°F / 175°C and continue baking until the outside is set and golden-dark brown, about another 20 minutes.

Serve at once with jam and butter.

Notes