Preheat oven to 350°F. Line three 8-inch cake pans with parchment rounds, and /or grease with non-stick or baker’s floured cooking spray.

Combine cake mix, eggs, milk, coconut rum, and butter, and beat with a whisk until just combined, scraping the sides of the bowl as needed. Divide evenly between three bowls to color your cake layers (I found a kitchen scale helpful for this part).

Color one layer with one large drop pink gel food color, the next with a smaller drop of gel food color plus 4 drops yellow liquid or 1 drop yellow gel food color, and the last with 4 drops yellow liquid or 1 drop yellow gel food color (to make a pink, orange, and yellow layer).

Bake cakes in the center of the oven for 29-35 minutes, or until a toothpick inserted into the middle comes out clean. Cool completely before frosting. (This is a great time to prep your frosting!)

Divide your frosting into 1 larger and 3 smaller parts – I used about 2/3 of one container to fill and crumb-coat my cake, and colored the rest of the frosting and used it to cover the cake. (To be honest, if I were doing the cake over I’d probably use 3 containers of frosting; apparently I use more frosting than most!)

Divide the remainder of your frosting into 3 parts, and color one pink, one orange (pink+yellow) and one yellow.

Once your cakes are cool, level them (if needed). This can be done with a cake leveler or a large serrated knife and a ruler. Place a smear of frosting on your cake circle (to keep the cake from sliding while you decorate it) and center your first cake layer in the center of the circle. Spread the layer with frosting and add the next layer on top. Repeat the process with your remaining cake layers.

Now you're ready to crumb-coat . If you're unfamiliar with crumb-coating, it's just what it sounds like – spreading a thin layer of frosting over the entire outside of the cake to keep crumbs out of your final layer.

Once your crumb coat has set (this takes about 5-10 minutes in the fridge), add frosting in three layers – I put the pink at the base, orange in the middle, and yellow on top. I used an offset spatula to spread the frosting and a large cake scraper to smooth. Once your cake is covered, place it into the fridge to set the frosting.

Place heavy cream and white chocolate chips in a microwave-safe bowl, and microwave on 50% power in 30-second intervals until smooth, stirring in between. Add gel color and stir until smooth.

When your ganache has cooled to a moderate temperature – it should feel slightly warm and still be fairly liquid – transfer it to a piping bag or squeeze bottle. Squeeze about ¼ cup of the ganache into the cocktail glass, and then quickly invert the glass over the cake, pressing the glass into the cake at an angle (see video above for an extra guide on this step). Slowly drizzle ganache away from the glass, letting it fall down the edge of the cake to create drips.

Add maraschino cherries, pineapple chunks, and orange slices to the top of your cake! I skewered the pineapple and cherries with cocktail sticks, and added orange slice spirals to the back of the cake behind the glass. Pipe a few frosting swirls around the decorations as well - if you have any frosting left!

Annnd you’re done! Step back and admire your cake!!