Preheat a griddle or large frying pan.
Whisk together in a large bowl:
1 cup all-purpose flour
½ cup sugar
⅓ cup unsweetened cocoa, sifted
2 teaspoons baking powder
¼ teaspoon baking soda
¼ teaspoon salt
Whisk together in another bowl:
1 ¼ cups milk
4 tablespoons (½ stick) unsalted butter, melted
2 large egg yolks
1 ½ teaspoons vanilla
Pour the wet ingredients over the dry ingredients and gently whisk them together, mixing until just combined.
¾ cup miniature semisweet chocolate chips or finely chopped semisweet or bittersweet chocolate
Beat until the peaks are stiff but not dry.
Fold into the batter:
2 large egg whites
Spoon ¼ cup batter on the griddle for each pancake, nudging the batter into rounds. Cook until the top of each pancake is speckled with bubbles and some bubbles have popped, then turn and cook until the underside is lightly browned. Serve immediately or keep warm in a 200-degree oven while you finish cooking the rest.
Serve with sweetened whipped cream or crème fraîsche and chocolate sauce.
Recipe Credit: The Joy of Cooking