1 1/3 cups all-purpose flour (GF for gluten free)
1/4 cup (25 grams) cocoa powder
1/2 teaspoon baking powder
1/2 teaspoon salt
1/2 cup (1 stick or 113 grams) unsalted butter, at room temperature (margarine for vegan)
1/2 cup, plus 2 tablespoons (91 grams), confectioners' sugar
1 egg (1/4 cup egg substitute, or 1T flaxseed combined with 3 T water, for vegan)
1/2 teaspoon vanilla extract
Lightly spray a standard muffin tin with non-stick cooking spray; set aside.
In a small bowl, combine the flour, cocoa, baking powder, and salt; set aside.
In a large bowl, or the bowl of a standing mixer, cream the butter until light and fluffy. Add the sugar and beat until thoroughly combined and fluffy. Stir in the egg and extract(s) until combined. Sprinkle half of the flour mixture into the bowl and mix until just combined. Add the remaining flour, mixing until until thoroughly combined.
Cover and chill for 20 to 30 minutes.
Preheat oven to 325 degrees (165 C).
Remove the chilled dough from the refrigerator and press three tablespoon portions of dough into each muffin cup, being sure to work it up the sides to form cups.
Bake for 20 to 23 minutes. Transfer to a wire cooling rack and allow to cool completely before serving.