French Chocolate Almond Cake

From Moosewood Restaurant New Classics
Be sure the ingredients are at room temperature—including the eggs, which can be warmed in a bowl of hot tap water for 10 minutes. 
We prefer making it without the optional black pepper and cinnamon

Yields a single 8-inch layer cake
Preparation time: 40 minutes
Baking time: 25 minutes
Cooling time: 10 minutes

1 teaspoon instant coffee granules (we used 2 Tbsp espresso)
2 tablespoons hot water
4 ounces good-quality bittersweet chocolate or semi-sweet chocolate chips
l/3 cup butter, at room temperature
l/2 cup sugar
3 eggs, separated (make sure to separate well)
1/3 cup unbleached white flour
l/3 cup finely ground almonds
* 1/4 teaspoon ground cinnamon (optional)
* 1 teaspoon ground black pepper (optional)
1/4 teaspoon cream of tartar
pinch of salt
2 tablespoons sugar
2 tablespoons confectioners' sugar 

Preheat the oven to 350°. Butter an 8-inch springform pan and dustwitfc flour. Stir together the coffee and water in a small saucepan. Add the chocolate and warm on low heat, stirring with vigilance until smooth and blended. Remove from the heat and set aside.

In a medium bowl beat together the butter and sugar with an electric mixer or whisk, until light and creamy. Add the egg yolks one at a time, beating well after each addition. Beat in the reserved melted chocolate mixture. 

In a small bowl, stir together the flour and ground almonds. If using, add the cinnamon and pepper. Set aside. 

Using an electric mixer or a whisk, whip the egg whites in a sturdy bowl until white and foamy. Add the cream of tartar and salt and whip until the whites form soft peaks when the beaters are lifted. Add the sugar and continue to whip until the whites are stiff and glossy. 

Now combine the mixtures. Fold the flour mixture and the beaten egg whites alternately into the chocolate mixture in two or three batches. Use a gentle, thorough touch so the batter is blended but light and airy. This is what gives the cake its melt-in-your-mouth texture. Pour the batter into the prepared pan. Bake the cake in the center of the oven for about 23 minutes. When done, the top of the cake will be slightly cracked, a few crumbs will adhere to a toothpick inserted about 2 inches from the edge of the pan, and the center of the cake will be soft and slightly puffed. 

Cool on a rack for about 10 minutes. Run a knife around the outside of the cake and remove the sides of the springform pan. Invert the cake onto the rack to remove the bottom of the springform pan. Then invert back onto a serving plate, cracked side up. Sprinkle with the confectioners' sugar and serve at room temperature. This cake is at its very best when served the same day.