With the mixer running on low speed, add the dry ingredients and milk to the wet ingredients until combined. Make sure there are no large lumps at the bottom of the bowl. Batter will be slightly thick.
Prepare a 9x13 pan and spray with non-stick coating. Pour the batter evenly into the pan. Bake for 25-27 minutes or until a toothpick inserted in the center comes out clean. Allow the cake to cool completely in the pan; set on a wire rack.
Remove only 2-3 cake balls from the refrigerator at a time. Keep the rest cold! 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 - 3/4 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, box (flip the box upside down and poke the lollipops into the bottom of the box) or even tall shot glasses work. 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!