INGREDIENTS
6
Egg whites, large
2 tbsp
Lemon juice, fresh
1
bar semisweet chocolate broken into pieces
1 1/2 tbsp
Baking powder
3 1/3 cups
Cake flour
3/4 tsp
Kosher salt
2 1/4 cups
Sugar
1 tbsp
Vanilla extract, pure
1
Cooking spray
3/4 cup
Butter, unsalted
1 3/4 cups
Milk