Flourless Chocolate Cake

1. Stage

The egg whites need to stand at room temperature for 30 minutes, so separating the eggs is your first task. Since the egg whites will be beaten, take care to not get any yolk into the white, which would prevent them from whipping properly.

2. Stage

Preheat the oven to 350°F. In a heavy saucepan, melt the butter, 1/4 cup of the sugar and both types of chocolate over low heat, stirring constantly. Let cool until the mixture is lukewarm.

3. Stage

In a large bowl, beat the egg yolks until thick and lemon-colored, about three minutes. Beat in the vanilla. Slowly beat in the chocolate mixture until the batter is a uniform color.

4. Stage

In a separate clean bowl and with clean beaters, beat the egg whites on medium speed until soft peaks form. Editor's Tip: The eggs should start turning glossy and take on a distinct form, but they should flop or sag when you lift the beaters. (You don't want to overbeat at this point, because you're not done beating!)

5. Stage

Gradually add the remaining sugar, 1 tablespoon at a time, beating on high speed until stiff peaks form. Editor's Tip: Stiff peaks will look glossy and hold their shape when you pull up the beaters. Do not over beat the egg whites (they will start to look grainy and liquid will pool in the bottom of the bowl—this is a sign you need to start over with new eggs).

6. Stage

First, stir a small amount of egg whites into the chocolate mixture. This dilutes the heaviness of the chocolate mixture, making it easier to integrate with the beaten egg whites. Then, slowly and gently, fold in the remaining egg whites. Always do a final fold that reaches all the way to the bottom of the bowl, where unmixed batter likes to hide. Editor's Tip: To fold egg whites means to gently work them into the batter with slow, delicate lifting and scooping motions, rather than with the rough spinning of a stir. Here's a detailed guide to folding ingredients, which preserves the volume of the whipped egg whites. In flourless cake, this is especially crucial for achieving the proper fudgy but still cakey texture of the cake.

7. Stage

Gently pour the batter into a greased 9-inch springform pan. Place on a baking sheet, and set on the middle rack of the oven. (The baking sheet makes it easy to move the cake in and out of the oven without tipping the batter.) Bake until the cake is just set, 28 to 30 minutes (but, if your oven runs hot, start checking earlier). The edges of the cake will be puffed up and set, but the center should still jiggle slightly when touched. A toothpick inserted in the center will come out with a few moist crumbs. Err on the side of underbaking, since the cake will continue to cook (and you want it to be a bit fudgy).

8. Stage

Cool the cake in the pan on a wire rack for 20 minutes. Carefully run a knife around the edge of the pan to loosen it, then remove the sides of pan. Decorate, if you like, before serving—ideas below! Editor's Tip: You may eat it warm, but the cake will be more delicate; the crumb will reach optimal fudge levels when no longer warm.