- 5 tablespoons (2½ ounces) butter
- 2/3 cup plus 4 tablespoons sugar
- 1¼ cups maple syrup
- 1 cup (4 ounces) finely chopped walnuts
- 1 cup whole milk
- 9 eggs
- 3 tablespoons plus 1 teaspoon flour
- ¼ teaspoon salt
- 1 tablespoon cornstarch
- 1 tablespoon brandy
- Pinch of cream of tartar
- Twelve 4-ounce or eight 5-ounce ramekins
- Candy thermometer
- Stand mixer
- See “Souffle Guidelines” in the Notes section, below
- Prepare the souffle molds:
- Melt 3 tablespoons of the butter and generously grease your souffle ramekins. Refrigerate the buttered ramekins and then butter them again. Dust the insides of the ramekins with 3 tablespoons of the sugar and return them to the refrigerator. Keep the remaining butter at room temperature.
- Make the pastry cream:
- Boil the maple syrup in a heavy-bottomed saucepan over medium-high heat until the syrup reduces by half and registers 240°F on a candy thermometer. If you do not have a thermometer, test the syrup after it has boiled, foamed, and reduced somewhat. Drop a fork tong of syrup on the counter-if it dries in a mound, scrapes off the counter cleanly with your fingernail, and is somewhat pliable and gummy between two fingers, it is ready. Remove from the heat and let cool for 5 minutes. Add the walnuts and milk and reheat until the syrup dissolves in the milk.
- Meanwhile, separate the 9 eggs, placing the whites in the bowl of a stand mixer; place 7 of the yolks in a medium bowl, and reserve 2 yolks in a small bowl to use later in the recipe. Briskly whisk the 7 yolks with the flour, salt, and cornstarch, making sure that the mixture is smooth with no lumps or streaks of white remaining. While continually whisking, add about half the hot milk mixture to the egg yolk mixture to warm it, then whisk the yolk mixture into the remaining hot milk in the pan.
- Bring the custard to a boil over mediumhigh heat, whisking continuously and making sure to scrape the bottom of the entire pan. Once the mixture boils for 20 seconds and thickens, remove it from the heat and stir in the remaining butter and the alcohol. Transfer the custard to a clean stainless-steel bowl and allow the mixture to cool, stirring every 2 to 3 minutes.
- Make the meringue (see “Acid in egg white foams” in the Notes section, below):
- Combine 2/3 cup plus 1 tablespoon of sugar and 3 tablespoons water in a small saucepan over medium heat and attach a candy thermometer to the side of the pan. Simultaneously place the 9 egg whites in the bowl of a stand mixer and whisk on medium-high speed. Once the egg whites begin to foam up, add the cream of tartar.
- When the egg whites are completely foamy and begin to hold the lines of a whisk, turn the heat under the pan of sugar syrup to high. Once the sugar syrup has come to a rolling boil and reaches 225°F to 230°F, gradually add the remaining 2 tablespoons of sugar, 1 teaspoon at a time, to the egg whites. As you add the sugar, the whites should become shiny and gain volume. If you see the whites beading (small lumps of egg whites forming on the side of the bowl), you have whipped them too dry; slow the machine down and add the remaining sugar.
- Once the sugar syrup on the stove reaches 248°F quickly, in a slow continuous stream, pour the hot syrup into the egg whites with the mixer set on a medium-high speed. The whites should still gain more volume and take on a satiny white color. Continue to whip the meringue on medium-high speed until it stiffens and cools, 3 to 5 minutes.
- Fold the meringue into the pastry cream (see raw egg yolks in pastry cream for souffle):
- Whisk the remaining 2 egg yolks into the maple walnut pastry cream. Add about a quarter of the meringue to the maple walnut pastry cream to lighten it and then add the remaining meringue. Place a spatula in the center of the bowl, scrape the bottom, and bring the bottom over the top. Rotate the bowl 45 degrees and continue folding until all the egg whites are incorporated.
- Fill the prepared ramekins:
- Using a rubber or plastic spatula, fill the prepared ramekins with the mousse, avoiding leaving any air pockets under the mousse in the ramekins. Flatten the tops of the ramekins with a metal spatula, scraping any excess mousse back into the bowl. Clean off any bits of mousse that might have dripped onto the sides of the ramekins.
- Bake the souffle:
- You can now either bake your souffles or place them in the refrigerator, covered, for up to 4 hours or in the freezer for up to 24 hours. Before baking frozen souffles, allow them to sit out at room temperature for 1 hour. When you are ready to bake the souffles, preheat the oven to 375°F. Bake the souffles until they rise over the rims by about ½ their original volume, 9 to 12 minutes in a convection oven or 15 to 20 minutes in a regular oven without a fan.
- Serving Suggestions:
- Serve these souffles as soon as they come out of the oven with a dollop of vanilla ice cream or crème fraîche.