Follow manufacturer’s directions on bag to make cake mix, making any size cake. Let cakes completely. Add cake to a food processor, pulse until it resembles fine crumbs. Add in buttercream a little bit at a time until cake is moist and can hold a ball shape, yet still slightly crumbly, knead the buttercream into the cake crumbs. Use a small disher and scoop out balls of cake mixture, roll the mixture into a tight ball and place on a parchment lined sheet tray. Repeat until all the cake mixture has been rolled into balls and freeze at least two hours, overnight is best. Place paper sticks into prepared cake balls and place back in the freezer. Melt white chocolate in the microwave, divide in half. Place blue coloring in one bowl and stir until desired color has been reached.
Remove cake balls from freezer and dip cake balls carefully into the chocolate until covered one at a time, dipping half of the balls in white chocolate and the other half in blue chocolate. Let the excess chocolate drip off. Swirl and tap gently if needed. Add the sugars while the chocolate is still wet, using white with white and blue with blue. It will harden quickly. Stick the decorated cake pop into a styrofoam block to finish setting.
Rather than baking fresh cakes, this is a perfect use of leftover cake bellies, cupcakes, or other trimmings!