Preheat oven to 350°F (177°C). Grease a 9-inch spring form pan.
Make the cake: Whisk the flour, baking powder, baking soda, and salt together in a medium bowl. Set aside. Using a hand held or stand mixer fitted with a paddle or whisk attachment, beat the butter and sugar together in a large bowl until creamed, about 2 minutes. Add the egg and vanilla extract and beat on high speed until combined. Scrape down the bottom and sides of the bowl as needed.
With the mixer running on low speed, add the dry ingredients and milk to the wet ingredients until combined. Manually whisk the batter to ensure there are no large lumps at the bottom of the bowl. Batter will be slightly thick. Pour the batter evenly into the prepared pan. Bake for 30-36 minutes or until a toothpick inserted in the center comes out clean. If the top begins browning too quickly in the oven, loosely place a piece of aluminum foil on top.
All the cake to cool completely in the pan set on a wire rack.
MAKE THE FROSTING: With a handheld or stand mixer fitted with a paddle attachment, beat the butter on medium speed until creamy, about 2 minutes. Add confectioners’ sugar, heavy cream, and vanilla extract with the mixer running on low. Increase to high speed and beat for 3 full minutes.
Crumble the cooled cake into the bowl on top of the frosting. Make sure there are no large lumps. Turn the mixer on low and beat the frosting and cake crumbles together until combined.
Measure 1 Tablespoon of moist cake mixture and roll into a ball. Place balls on a lined baking sheet. Refrigerate for 2 hours or freeze for 1 hour. Re-roll the chilled balls to smooth out, if needed. Place back into the fridge as you’ll only work with a couple at a time.
Melt the coating in a double boiler or microwave.
Coat the cake balls: Remove only 2-3 cake balls from the refrigerator at a time. Dip a lollipop stick about 1/2 inch into the coating, then insert into the center or the cake ball. Only push it about halfway through the cake ball. Dip the cake ball into the coating until it is completely covered. Make sure the coating covers the base of the cake ball where it meets the lollipop stick. Very gently tap the stick against the edge of the measuring cup to allow excess coating to drop off.
Decorate the top with sprinkles and place upright into a styrofoam block or box. Repeat with remaining cake balls, only working with some out of the refrigerator at a time. The cake balls must be very cold when dipping!
Coating will set within an hour. Store cake pops in the refrigerator for up to 1 week.
