Stuffed Potato Pancakes

Vanilla extract 1 teaspoon
Plain flour 200g (1 1/4 cups)
Baking powder 1 1/2 teaspoons (6g)
Cocoa powder 1 tablespoon (10g)
Instant coffee 1 teaspoon
Warm water about 2 tablespoons
A few chocolate chips (optional)
Baking dish dimensions 21x11x6 cm
Bake in a preheated oven at 170°C (338°F) for 35 to 40 minutes.