Chocolate Decadence Cake with Vanilla-Bean Raspberry Coulis

Makes one 8- or 9-inch cake

1 cup plus 2 tablespoons salted butter
7 ounces semisweet chocolate
2 ounces bittersweet chocolate
6 eggs, separated
3/4 cup granulated sugar
3/8 cup brown sugar
3/8 cup cake flour
3 tablespoons finely ground almonds
1/2 teaspoon cream of tartar
About 2 cups Vanilla-Bean Raspberry Coulis (recipe below)

Preheat an oven to 375F, butter an 8- to 9-inch springform pan, line the bottom with parchment paper and flour the pan.

In a large heavy-bottomed pan over low heat, melt the butter. Chop the chocolate into coarse pieces and add it to the butter, stirring constantly until the chocolate is just melted and smooth. Be careful not to overheat or the chocolate will turn grainy. The chocolate should not get much hotter than 115F; set aside.

In a medium-sized bowl, beat the granulated and brown sugars into the egg yolks just until mixed. While the chocolate is still warm, whisk the egg yolk mixture into it. Stir in the flour, and then the almonds. If the combined mixture has cooled, warm it over low heat, stirring constantly, until it is barely warm.

Over a double-boiler of simmering water, warm the egg whites slightly (egg whites will beat to a greater volume when warmed). Add the cream of tartar to the warmed egg whites. In a stand mixer with a whisk attachment, beat the egg whites and cream of tartar until they look creamy and form rounded peaks (they should not look flaky, a sign that they have been over beaten). Fold the egg whites gently into the chocolate without deflating the whites.

Pour the mixture into the prepared pan and bake for 30 to 40 minutes, until the cake is completely set around the sides but still has a soft and creamy circle, about 6 inches across, in the center. The center will wiggle just slightly when you shake the pan gently; it will continue to cook when you take it out of the oven. The cake will rise and crack around the edge and separate from the softer center. Cool thoroughly in the pan.

To serve the cake, turn it out, peel the paper off the bottom and serve with the Vanilla-Bean Raspberry Coulis.

Vanilla-Bean Raspberry Coulis
Makes about 2 cups

2 cups fresh or frozen raspberries
1/2 cup powdered sugar, or more to taste
1 tablespoon lemon juice, or more to taste
1/2 teaspoon vanilla extract

In a blender or food processor, puree the raspberries. Using a spatula, press the puree through a fine-mesh strainer, extracting as much liquid as possible. Discard the seeds and skin. Add the sugar, lemon juice and vanilla and stir until combined. Taste and add more sugar and/or lemon juice if desired.