1 cup all-purpose flour
1.5 tsp baking powder
1 tsp baking soda
1/2 tsp salt
5 large eggs, separated
1 3/4c sugar
2 Tbsp water
1/2 cup + 1 Tbsp cocoa
1 Tbsp instant coffee powder
2 sticks unsalted butter, room temperature, cut into 8 pieces
2 tsp vanilla extract
1/2 c + 2 Tbsp plain yogurt
Preheat oven 375F/190C and adjust rack to middle of oven. Butter 12-cup Bundt pan with butter and dust with flour. In a 2-cup mixing bowl, combine flour, baking powder, baking soda and salt with a spoon and set the mixture aside.
Assemble all the ingredients and a 1-quart mixing bowl conveniently near the food processor.
Using the metal blade of the food processor: Put the egg whites and 4 Tbsp sugar in the work bowl and turn the machine on. After 8 seconds pour the water through the feed tube while the machine is running. Process for about 2 mins., or until the egg whites are whipped and hold their shape. With a rubber spatula, gently transfer the egg whites to the mixing bowl. It is not necessary to wash the work bowl.
Process the egg yolks, remaining sugar, cocoa and coffee for about 1 min. Add the butter and process for about 1 minute, stopping once to scrape down the sides of the work bowl. Add the vanilla and yogurt and process for 5 seconds. Add the flour mixture and combine the batter by turning the machine on and off twice.
Spoon 1/4 of the egg white mixture onto the batter and turn the machine on and off twice. Run a spatula around the sides of the bowl to loosen the mixture. Spoon the remaining egg whites onto the mixture in a ring. Turn the machine on and off 3 times. Run a spatula around the sides of the bowl and turn the machine on and off once more.
Pour the batter into the prepared pan and cut through it with a knife to remove any air pockets. Bake for 35 minutes, or until the cake begins to pull away from the sides of the pan and a toothpick inserted in the center comes out clean. Let the cake cool in the pan on a rack for 10 mins. Then invert it onto a wire rack and remove the pan. Let the cake cool completely and front it with Mocha or Chocolate Frosting (recipe not included) or Nutella.
Makes 12 servings.