For a vegan variation, use ¼ cup melted, room temperature coconut oil in place of the butter; mix together all ingredients (except powdered sugar) in a bowl with a wooden spoon, then bake at 325°F for 10 minutes. However, the resulting cookie is not as rich and has a more crumbly texture; you may want to consider adding a bit more sugar in this variation to make up for the lost richness.