ingredientsvanilla cupcakes6 tbsp (84g) unsalted butter, room temperature (i useâ challenge butter)3/4 cup s (155g) sugar6 tbsp (86g) sour cream, room temperature2 tsp (10ml) vanilla extract3 large egg whites, room temperature1 1/4 cup s (163g) all purpose flour2 tsp (8g) baking powder 1/4 tsp sa