Life hack for OP and anyone else who ends up in this situation:

• Take boxed cake mix of your choosing.
• MOSTLY follow the package instructions. However:
• Add one extra egg (for example, if it calls for 2 eggs use 3)
• Substitute oil with 2x butter (for example, if the recipe asks for ⅓ cup oil use ⅔ cup melted butter.)
• Simple, easy, pro-tier cake.