Preheat your oven to 350°F (175°C). Grease a standard 9x5-inch loaf pan with butter or non-stick spray, then lightly dust it with flour.
In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt. Set aside.
In a large mixing bowl, use an electric mixer to cream the softened butter and granulated sugar until light and fluffy, about 3-5 minutes.
Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
With the mixer on low speed, alternately add the dry ingredients and sour cream to the butter mixture, beginning and ending with the dry ingredients. Mix just until combined after each addition.
Spoon about two-thirds of the batter into the prepared pan. Dollop half of the peach butter over the batter, then gently swirl it with a knife or skewer. Add the remaining batter on top and repeat with the remaining peach butter, swirling one more time.
Bake the pound cake for 50-60 minutes, or until a toothpick inserted into the center comes out clean or with just a few moist crumbs. Tent with foil if top browns too quickly.
Allow the cake to cool in the pan for about 15 minutes before transferring it to a wire rack to cool completely.