• Preheat oven to 350°F. Prepare a 15x10" baking pan with Baker's floured cooking spray, or grease and line the base with parchment paper.
• Combine melted butter, buttermilk, eggs, and vanilla in a large bowl and mix until combined.
• Add in cake mixes and stir until moistened (about 30 seconds), then beat on medium speed for about 2 minutes. Pour batter into prepared pan.
• Bake for 35-37 minutes, (or until a toothpick comes out clean). Allow to cool for 20 minutes before removing from pan. Cool completely before frosting (place cake in the fridge or freezer to accelerate the cooling process if desired). (This is a great time to make your frosting!)
• Once your cake is baked and cooled/chilled, use a large serrated knife to cut it into a 4-shape – I used a couple of pieces of paper to help me keep my cuts straight. (I like to make the frosting while the cake is chilling so I can crumb coat it as soon as it's cut - the crumb coat keeps crumbs out of the colored frostings, but it also helps keep the cake from drying out!)

Cream Cheese Buttercream Frosting

• Beat together softened cream cheese and butter; slowly add in powdered sugar alternating with milk until frosting reaches desired consistency. Add vanilla and salt if needed and beat until well combined.

Decorating

• For each of the sections below, pipe on small stars of frosting to cover the cake section with a piping bag fitted with a small open star piping tip. Cover the sections with your desired colors – the ones I used are below!
• Whether you make or buy your fondant, soften it slightly in the microwave before shaping your decorations.

Spiderman

• Cover section in red frosting. Melt candy melts and transfer to a piping bag with a tiny hole in the tip. Pipe a spider web onto the section - I started a circular pattern in the center swirling outward, and then added straight lines back into the center. It made a pretty convincing web!

Iron Man

• Cover section in red frosting. I bought cupcake toppers to use on this section of the cake; I couldn't find a fondant design to convey the superhero clearly enough in such a small section. I used small bits of silver leaf to add a bit of extra shine to that part of the cake - in hindsight I wish I'd have used gold; you can buy a set with both here!

Batman

• Cover section in black frosting. I printed a batman logo and cut out an oval and then the batman logo shape and used them as templates to cut the same shapes out of fondant. A bit of gel food color later we were good to go!

Captain America

• Cover section in blue frosting. This fondant work involves a little more time – cut out a small fondant star and a large, medium/large, medium/small, small fondant circle. The largest and medium/small circles I painted red, and the small circle was blue – the layers as you stack them should be red, white, red, blue, and then the fondant star. I know, a few steps – but they're easy steps and it looks super cool when you’re done!

The Hulk

• Cover section in purple frosting. I used roughly a 2-tablespoon lump of fondant to make the large Hulk fist shape, and about a thumb-sized amount of fondant to make the cupcake Hulk fists, shaping them with a toothpick and the blunt end of a metal skewer. You can use green fondant or use white fondant and paint it green – I’ve found it easier to get bright colors by painting white fondant, but the color’s not quite as even. Up to you!