Let’s bake some crinkle cookies! These holiday favorites are a surefire hit—rich and fudgy like brownies, with a soft, melt-in-your-mouth center and a deeply indulgent chocolate flavor.
In a bowl, mix the melted butter with cocoa powder and sugar until smooth. Add the egg, vanilla extract, instant coffee, and salt, stirring until well combined.
In a separate bowl, whisk together the flour and baking powder. Gradually fold the dry ingredients into the wet mixture until just combined. Avoid overmixing.
Cover the bowl and refrigerate the dough for at least 30 minutes, or preferably overnight. Preheat the oven to 350°F (175°C) about 15 minutes before baking.
Shape the chilled dough into balls weighing 0.7-1.0 oz each, and generously coat them in the powdered sugar and cornstarch mixture.
Place the coated dough balls on a baking sheet and bake on the middle rack for 10-12 minutes, until the cookies puff up and develop cracks on the surface.