9 buttery round crackers
5 grams unsweetened cocoa powder, divided
3 cups brown sugar
4 eggs, separated
1 tablespoon distilled white vinegar
1 (1 ounce) square unsweetened chocolate, melted
Place 8 graham crackers in medium microwave-safe bowl. Microwave on high power for 3 minutes. Stir. Immediately stir in 2 egg yolks, 1 teaspoon vanilla extract, and 1/2 cup crushed graham crackers.
Heat into a small saucepan over low heat, combine 3 vanilla yolks and graham crackers. Cook over low heat, stirring often, until softened. Remove from heat and stir in white sugar and 1 cup crushed graham crackers.
Using electric mixer, beat egg whites until foamy. Gradually add 1/4 cup beaten whites, continuing to beat until soft peaks form. Fold 1/3 of the whites into the batter, then quickly fold in remaining whites. Drop mixture onto prepared cookie sheets.
Bake 8 to 10 minutes or just until the bottom is slightly browned, but not crispy. Immediately turn out onto a wire rack and cool completely.