Mocha Confetti Cake

FOR THE CAKE:
Preheat oven to 350 degrees F.

Line the bottom of an ungreased angel food cake pan with parchment or wax paper: first place the pan on a piece of the paper and trace a circle. Cut out the circle, fold it in half, in half again, and in half once more. Lay the folded paper across the top of the pan with the paper’s curved edge at the outside rim and the point at the center. Mark where the tube hits the paper and trim off the point to that mark. Unfold the paper and smooth it into the bottom of the pan.

Stir together 2 tablespoons instant coffee, vanilla and 1/4 cup warm water in a small bowl until the coffee dissolves. Whisk in oil and 3 egg yolks; set aside. Pulse 3/4 cup semisweet chocolate chips in a food processor until finely grated; set aside. Sift 3/4 cup granulated sugar, flour and baking powder into a bowl; set aside.

Beat the 10 egg whites, cream of tartar and salt in a mixing bowl with an electric mixer on low speed until frothy. Gradually increase the mixer speed to medium-high and beat until soft peaks form. While still beating, slowly add the remaining 3/4 cup sugar and beat until semi-stiff peaks form. Fold the egg yolk mixture into the beaten egg whites with a rubber spatula, then fold in the grated chocolate chips. Sprinkle about 1/3 cup of the reserved flour mixture over the top and gently fold in; repeat with the remaining flour, adding 1/3 cup at a time.

Pour the batter into the prepared pan. Bake until a skewer inserted in the center of the cake comes out clean, 55 to 65 minutes. Invert the cake to cool completely, about 2 hours. (If the cake pan has no “legs,” invert it over the neck of a bottle).

Loosen the cake from the side and center tube of the pan with a narrow, sharp knife. Turn the cake out onto a wire rack and peel off the paper. Turn the cake right-side up.

FOR THE GLAZE:
Dissolve 1 teaspoon instant coffee powder in 1 tablespoon hot water in a small bowl. Add coffee liqueur (or water). Whisk in confectioners’ sugar until smooth, adding a little more liqueur or water if the glaze is too thick. Drizzle the glaze over the top of the cake with a spoon, tilting the cake to let some of the glaze drip down the side.

Put 1/4 cup semisweet chocolate chips in a small plastic bag and microwave on High until melted, about 1 1/2 minutes. Snip a tiny hole in one corner of the bag and squeeze the chocolate out in thin lines over the top of the glaze.

Transfer the cake to a serving plate and let the glaze and chocolate firm up for about 30 minutes before serving.