Cream butter, sugar, and brown sugar with an electric mixer on medium speed until light and fluffy, about 3 minutes. Add milk and vanilla, beating until incorporated.
Mix in flour and salt just until incorporated, then stir in chocolate chips. Refrigerate until ready to use.
To make the pancakes:
Sift flour, cocoa powder, sugar, baking powder, baking soda and salt together into a medium bowl. In a large measuring cup, whisk eggs, butter and milk together. Pour the wet ingredients over the dry, and gently mix just until combined – the batter will be somewhat lumpy and thick.
Heat 1 teaspoon of oil in a 12-inch nonstick skillet set over medium heat (you could use butter too if you’d rather). Once the oil starts shimmering, use paper towels to wipe the pan so only a thin, even coating of oil covers the bottom and sides.
Use a 1/4 cup measure to portion the batter into the pan. Spread it into roughly a 4-inch circle. Drop about 5 marble-sized pieces of cookie dough over the surface of each pancake. Cook on the first side until the edges are set and bubbles form on the surface. Use a spatula to flip the pancakes and cook on the second side until cooked through.
Repeat with remaining batter, adding more oil to the pan if necessary.
Notes
To keep pancakes warm, preheat oven to 200 F. Spray a wire rack with cooking spray and set it inside a baking sheet then place the baking sheet in the oven.
This recipe makes more cookie dough than you’ll need for the pancakes. The extra makes a delicious snack or you can freeze it to use later.