In a small bowl mix the dry ingredients (flour, baking powder, baking soda, salt, and nutmeg). Whisk until thoroughly incorporated.
2 ½ cups cake flour, 1 ½ teaspoons baking powder, ½ teaspoon baking soda, ½ teaspoon salt, ¼ teaspoon ground nutmeg
In the bowl of a stand mixer, fitted with the paddle attachment, or large mixing bowl, cream the butter, granulated sugar and vanilla extracxt on medium speed until light and creamy, 1 to 2 minutes.
4 tablespoons unsalted butter, ½ cup granulated sugar, 1 ½ teaspoon vanilla extract
Add the eggs, mix on medium for 30 seconds, or until well incorporated, scrape down the bowl and paddle.
2 large eggs
Add one-third of the flour mixture, mix on low until just incorporated, some streaks of flour may remain. Add half of the sour cream, mix on low until just incorporated. Continue adding one-third of the flour mixture and the remaining half of the sour cream, mixing on low speed and scraping down the bowl and paddle as needed. Finish with the final third of flour, mix on low until just incorporated.
¾ cup sour cream
Cover and chill dough for one hour.