In this class, we certainly made mousse and fillings, but they (mostly) couldn’t stand on their own, so we made cake and lots of tart dough, too.
Mousse doesn’t appear complicated, but there’s plenty of technical information to learn. A mousse consists of a base (the main flavor), a binder, and a lightener. The base can be fruit puree, custard, or chocolate. The binder (which obviously holds it all together) is usually gelatin or pectin. Vegan recipes often call for agar, which can be unpredictable and therefore difficult to work with. Lighteners are beaten egg whites, whipped cream, or a combination of the two. Lighteners lighten the texture, not the calorie count.
Bavarian cream is like a mousse, but it’s molded, so it uses more gelatin. Mousses are often creamy and spreadable and can be used as fillings.
Mousseline in the savory kitchen is a sauce that’s a combination of hollandaise and whipped cream. In the pastry kitchen, a mousseline is a filling that’s a combination of pastry cream and butter cream, pastry cream and whipped cream, or butter cream and Italian meringue. Mousseline is heavier than mousse.
Chibouste, which we made last week, is pastry cream lightened with Italian meringue and stabilized with gelatin. Curd is acidic fruit juice mixed with eggs and sugar and cooked until it thickens.
Almond cream is amazingly versatile. It can be mixed with flour and baked as a cake, it can be baked on its own as a flourless cake, and it can be used as a tart filling.
Fruit fillings for pies and tarts need a thickener to keep the juice from running everywhere when the pie or tart is sliced. Flour is a common one, and it’s good for any fruit that’s not acidic. It’s not the best choice for visible fruit filling because it leaves the filling looking dull. Cornstarch makes the filling somewhat glossier, but arrowroot and tapioca give the highest gloss. Cornstarch is a good all-purpose thickener, but it’s not the best one to use with acidic fruits. Instant tapioca is a good thickener, but it does leave the little balls of starch; tapioca starch is pulverized tapioca that looks like cornstarch, tolerates prolonged cooking and freezing, and is very shiny. Arrowroot tolerates high heat, prolonged cooking, and freezing, and it works well with acidic fruits, so it’s a good thickener to use in curds; fruit curds made with arrowroot can be frozen.
Obviously our mission in the kitchen was to make mousse and fillings and things to fill. We started out making chocolate cake. We used a traditional genoise recipe, which, instead of using a chemical leavener (baking soda, baking powder), relies on expansion of the air beaten into the eggs. You beat the eggs way longer than you’d imagine, then you gently but quickly fold in the dry ingredients, turn the batter into the pan, and get it right into the oven so the heat of the oven can expand the air in the batter, which lifts the cake. It’s like magic!
After the cake had cooled, we sliced off the top, returned the cake to the ring, then soaked the cake with raspberry syrup and topped it with raspberry jam. Then we popped the cakes in the freezer.
Then we moved on to tart dough, which has to be chilled before you roll it out. The trick to tender pie and tart dough is to work it as little as possible so you don’t encourage a lot of gluten development. Some gluten develops, and that’s fine because that’s what holds the dough together, but giving the dough a rest allows the gluten strands to relax, and letting it rest in the refrigerator keeps the fat cold; you want the fat to be good and cold when the dough goes into the oven so it can melt in the oven and release steam to flake the crust.
For both the cakes and the tart shells, we used cake rings set on baking sheets, which is the traditional way in France. Julia Child was taught to do it this way at the Cordon Bleu, and she shows it in Mastering the Art of French Cooking.
Then we got down to the fillings and mousse.
Chocolate mousse has a lot of steps, but it’s pretty straightforward, and the result is delicious. The base is obviously chocolate. The binder is gelatin, and sheet gelatin is used in the professional pastry kitchen. Instead of dissolving powdered gelatin in cold water and then heating the mixture and cooling it again, you use something that looks like strips of acetate. The recipe specifies how many sheets, and you soak those in water; each sheet equals about 1 teaspoon of powder and absorbs 2 teaspoons of water, so it’s easier to handle, and it doesn’t need to be heated or cooled. The lightener is beaten eggs and whipped cream. We topped our cakes with the mousse, filling the ring to the top, then popped them back in the freezer.
For fillings, we made blueberry, pecan, and apple pie fillings and a kind of fruit custard. We made full-size apple pies. My partner wanted a plain, old-fashioned top crust with slits, and she liked the idea of using the Greek letter π, which is what I do at home.
Louise, a chef-instructor in the culinary program, has been sitting in with us on Wednesdays to learn more about pastry, and she got creative with her top crust, which I like a lot.
We made tartlets with the pecan filling.
Then we ran out of time. Well, we could’ve stayed another couple of hours and finished, but Chef Sharon told us we could finish everything in the next class.