1 Combine the dry ingredients: Whisk the flour, baking powder, baking soda, and salt together in a bowl and set to the side.
2 Make the cookie dough: In the bowl of a stand mixer with a paddle attachment, beat butter and sugar together until light and fluffy, about 3 minutes. Beat in the eggs one at a time, scraping down the bowl after each addition.
Beat in the vanilla and sour cream until combined. Then, in two separate additions, beat in the flour, scraping the bowl after each addition. This will create a soft and fluffy dough.