Break the cake layer into large chunks and place it in the bowl of a stand mixer.

Mix on a medium speed with a paddle attachment to break down the cake. If you don't have an electric mixer this can also be done by hand.

Mix in 1 Tbsp of frosting until the cake mixture has a texture similar to play dough. It should be soft and pliable but not greasy. If your cake mixture hasn't come together yet add more frosting 1 tsp at a time until it does. Cover and set aside.

Place the finely chopped chocolate (white, milk, semi-sweet or dark) or candy melts in a large heatproof bowl.

Heat for 30 seconds at a medium high-heat (I do a power level 7 out of 10). If you don't have a microwave you can also use a double boiler.

Remove from the microwave and stir the chocolate. It won't be melted much yet, but this helps make sure the chocolate is evenly heated and that certain areas don't overheat/overcook.

Heat for an additional 15 seconds on medium-high power and stir again. If you're using chocolate, check the temperature of the chocolate with your food thermometer between intervals and make sure it doesn't go above 90 F / 32 C.

Repeat until the chocolate is mostly (but not fully melted). Let it sit for a minute, then give the chocolate one more stir to make sure it's nice and smooth.

Use a clean / food-safe paint brush to brush an even layer of melted chocolate or melted candy melts all around the mold.

Immediately insert a popsicle stick in and out of the mold to keep the opening free of chocolate.

Chill the mold in the fridge (or freezer if you're using candy melts) for about 3 minutes or until the chocolate is firm to the touch.

Paint on a second layer of melted chocolate, being sure to add a little extra chocolate around the edge of each cavity. Insert and remove a popsicle stick again.

Refrigerate for another 3 minutes (or freeze if you're using candy melts) until the chocolate is firm to the touch.

Press the cake mixture into a chocolate-lined cavity, filling it 1/8 inch below the edge of the silicone mold.

Insert the popsicle sticks into the molds, then top each mold with additional chocolate and smooth using an offset spatula. Repeat with the remaining molds.

Refrigerate until the chocolate is firm to the touch (2-3 minutes), then carefully remove the cakesicles from the mold and decorate as desired.