- First, preheat the oven to 375°F. Prepare a non-stick cookie sheet with parchment paper. 
- Next, in a medium bowl, whisk together the flower, baking powder, and salt. Set aside. 
- Moreover, in your stand mixer bowl with the paddle attachment, cream together the butter, granulated sugar, and brown sugar on medium-low speed until well-blended, about 1-2 minutes. 
- Similarly, mix in the egg and vanilla.  
- Further, add sour cream and mix until well-blended. 
- Next, set the mixer to low speed. Slowly add in the dry ingredients, mixing just until they are blended in.  
- Then, with your hands buttered, scoop the dough out in 1 tablespoon portions and roll each into a ball.  
- Place each ball on the cookie sheet. 
- Bake in the preheated oven for about 15 minutes until the bottoms are a light golden brown. Transfer them to a cooling rack and allow them to cool.