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.
3 Fold the dough briefly in the bowl: Using a stiff rubber spatula, fold the dough a few times inside the bowl – scoop down the side of the bowl and underneath the batter, then lift up and fold the dough over on itself. Give the bowl a quarter turn and repeat. Repeat this a few times until the dough is smooth.
4 Chill the dough: Press a piece of…