– 1½ cups 3 sticks butter – 3 cups light brown sugar, packed – 3 large eggs – 1½ teaspoons pure vanilla extract – 3 cups all-purpose flour – 1 tablespoon baking powder – 1/2 teaspoon kosher salt – 2 tsp pumpkin pie spice – 2 medium apples, peeled, cored, and thinly sliced