How to make mousse, according to Food52's resident baker

Mousse, for me, is the ultimate fancy-pants dessert — at least ever since someone explained to me the difference between moose and mousse (both are impressive, but one is decidedly more delicious).

There are lots of different kinds (including this of wonderfully easy chocolate mousse recipe, with only a few ingredients), but the traditional method is worth learning because it's so versatile. Since the dish has so few ingredients, basic tweaks can yield dozens of different flavor combinations. The sky's the limit for creating your own custom mousse recipe.

How to make mousse

1. What is mousse?

But first, what is mousse? Mousse is the stuff of dessert dreams: incredibly light and also ridiculously rich. At its most basic, mousse is made by folding aerators into a base. These aerators can be whipped cream, meringue (egg whites + sugar), pâte à bombe (whole eggs and/or egg yolks + sugar), or a combination. The base can be a whole host of things: melted chocolate, puréed fruit, fruit curd, or a prepared custard (like pudding or crème anglaise, a "vanilla sauce" of dairy base and thickened with egg yolks made on the stovetop).

Many mousse recipes call for gelatin to help set the mousse. (Agar agar can be an appropriate substitute should you be avoiding gelatin.) Other recipes, however, don't require any thickener at all; this is usually when the base ingredient is chocolate, which helps the mousse set firm.

Mousse is a delicious dessert on its own, portioned into serving dishes before it's set, and it can also be manipulated to be a layering component in cakes (think those gorgeous, rich, and seemingly unattainable cakes lined up in fancy bakery cases).

2. Mise en place (for real)

Mousse is not often classified as "easy," but the reality is that you're working with a pretty short ingredient list and the method is straightforward. That being said, you're dealing with time- and temperature-sensitive ingredients, which means it's extra important to be prepared.

Read through your recipe completely, and grab all the tools you'll need ahead of time. From there, prep your ingredients, from least to most sensitive (more on this later). Then, it's just a matter of mixing to combine — seriously! It may not be boxed cake mix, but if everything is in place when you begin, it's not so far off.

Photo by Bobbi Lin

3. Get your equipment ready

You don't necessarily need special equipment to make mousse, but it's not an all-in-one-bowl sort of situation (the deliciousness makes up for the dishes, I think).

• You'll need a bowl for the water and gelatin, if the recipe uses gelatin. Be sure to use a heat-safe bowl so you can easily melt the gelatin later. I like to use a wider, shallow bowl so there's more surface for the gelatin to bloom easily (my favorite is a wide ramekin, like the kind for for crème brûlée).
• Place your base in a bowl large enough to accommodate it and all the other ingredients once they're added.
• Next, you'll need a bowl for each of your aerators and something to aerate them with: a whisk if you've got insane arm strength or, more likely, an electric stand or hand mixer. Many mousse recipes (including the ones featured in this article) use multiple aerators, which can be frustrating if you only have one bowl for your stand mixer. I avoid this by using multiple types of tools. I like to whip cream using my immersion blender, which then leaves my stand mixer free for whipping meringue. Alternatively, an electric hand mixer is great for whipping cream, meringue, and/or pâte à bombe — you just have to wash the beaters in between, and keep the different aerators in their own bowls.
• Have a rubber spatula ready for mixing, and something ready for portioning: a pastry bag or a liquid measuring cup with a spout.
• Ready your vessels for the mousse once it's time to portion.

4. Ingredients

Mousse is made up of just a few ingredients: the base, the aerator(s), the sweetener (which is usually added to the aerator), and the thickener (which is optional, depending on the recipe).

The base:

The "base" of a mousse recipe is the main flavoring component. It can be as simple as melted, slightly cool chocolate or puréed fruit. It can also be a little more complex: a prepared fruit curd, or a custard like pudding or crème anglaise.

Here's a good guideline as to when to use each base:

• If you're going for a chocolate mousse, chocolate alone will likely be your base. This is a bonus because you can also refrain from adding a thickener more easily, as chocolate naturally sets up under refrigeration.
• If you're aiming for a fruit mousse, you'll start with puréed fruit or a fruit curd.
• For any other flavors, like vanilla, coffee, or caramel, you'll likely start with a custard base, which can easily be flavored in a variety of ways.

Whatever your base, make sure it is at room temperature unless the recipe says otherwise. Too warm, the base may deflate the aerators. Too cold, the thickener may begin to set up the mousse before you're finished incorporating all ingredients.

The aerators:

Mousse recipes always contain an aerator, and they often contain more than one. What's most important to remember is which aerator is the most stable so that when you begin preparing your ingredients, you work in the right order. No matter what aerators you're using, you'll add them in order of most stable to least stable. Usually, the sweetener is added to the aerator — if multiple aerators are used, a portion of the sugar may be added to each.

• Whole eggs and/or egg yolks are the most stable aerator. Sweetener, or a portion of the sweetener, is added and the mixture is warmed over a water bath to heat the eggs to safe temperature (140° F). Whisk the mixture constantly until it is pale and thick and all of the sugar is dissolved. Most recipes will require the mixture to be whipped further with an electric mixer until it has reached full volume (usually 3 to 4 minutes).
• Whipped cream is the second most stable aerator. I usually whip my cream to soft peaks, throw a whisk into the bowl, and chill the whole thing until I'm ready to use it. A few quick whisks when I'm ready to begin folding takes the cream to medium peaks — the ideal texture for mousse. While you can add the sweetener or a portion of it to the cream, you can also successfully whip the cream properly without any sugar.
• Egg whites, usually in the form of meringue, whipped with the sweetener or a portion of it are the least stable aerator. For safety, the eggs are warmed over a water bath to 140° F before they are whipped to medium peaks. As the least stable aerator, the egg whites should only be whipped just before you're ready to mix the mousse.

The thickener:

Traditionally, mousse is made with gelatin. The gelatin should be bloomed in cool water or 5 minutes, then melted before adding to the base.

The amount of gelatin can be altered depending on the desired texture. For example, a mousse that's contained inside a glass or other vessel can have less gelatin than a mousse used as a filling for a cake. Agar agar can be used as a substitute if you're trying to avoid gelatin, and it should be handled in the same way.

Some recipes — usually, recipes that use chocolate as a base, because it thickens on its own under refrigeration — don't require a thickener at all.

Photo by Bobbi Lin

5. Mixing the mousse

The first steps of mixing are very simple. If you're using gelatin, stir it into the base. Remember to note the temperature of the base so that it's not too warm or too cool when the gelatin is added. If you're not using gelatin, proceed to the folding.

6. Folding

To mix a mousse, the aerators are gently added into the base. Rather than mixing, the aerators are folded into the base. If there's only one aerator in the recipe, you can fold it in on its own. Again, if you're using more than one aerator, add them one at a time in order from most stable to least stable (first whole eggs or egg yolks, then whipped cream, and, finally, meringue).

In goes the most stable aerator: the egg yolks! (Photo by Bobbi Lin)

It's best to "temper" the mixture by adding a small amount — about 25% — of the given aerator to the base and mix to combine. During this time, it's OK to mix slightly more vigorously.

This will lighten the base, making it easier to incorporate the remaining aerator. Add the remaining aerator in 2 or 3 additions and gently fold, just until the aerator is incorporated. Repeat with the next aerator, until all the ingredients are added to the mousse. Remember that the more you mix the mousse, the more you're deflating each aerator: It's important to work quickly and minimally.

Now fold in the second most stable — the whipped cream — a little at a time.

Light and airy and almost ready to eat! (Photo by Bobbi Lin)

7. Portioning

Once the mousse is fully mixed, gently transfer it to a pastry bag. (Alternatively, you can transfer it to a liquid measuring cup with a spout.)

Quickly divide the mousse among the serving containers. If the mousse has cooled down significantly already, it may begin to set up right away. If it's still at room temperature, you'll have a little more time to work with it.

Photo by Bobbi Lin

8. Let it set

The mousse must set in the refrigerator before it can be served, which will most likely take 15 to 30 minutes. If you're layering the mousse, each layer must set before you add the next. The same is true of using the mousse in a cake: The mousse must set before you can unmold and finish the cake.

The mousse will keep for a few days, which makes it an excellent make-ahead dessert.

Recipe: Triple Layer Mousse