This Fiesta Sombrero Birthday Cake was for my son's birthday party. I don't know where he got the idea- he was only 6- but for some reason he had heard the word "fiesta" and decided that would be great!
The base is a chocolate cake mix for the using a standard sheet cake pan. A helpful tip- if you're doing a whole sheet, get the aluminum insert that goes in the middle. You fill it with batter, set it in the middle, pour the batter around it and leave it there while baking. After baking you take it out and plug the hole. This helps the center of the cake cook so you don't end up with a gooey mess.
I torted the bottom with a cake leveler, filled it with buttercream and frosted the top and sides. To get the top smooth, I waited for the buttercream to crust a little, then put a sheet of wax paper lightly on top and smoothed very gently with my hand. I used a star tip to make the shell borders.
The sombrero is made with rice crispie treats. I just made a cone shape with my hands, rolled in the counter to smooth the sides, then set it on top of a flattened circle of rice crispie treat mixture. I used a sharp knife to cut strips from red and green fruit roll-ups for the hat bands and then piped on the red dots and the string decoration on the brim. I got cherry-flavored gummy peppers from Oriental Trading and stuck them on the sides and on top, then piped the letters.
Since I live in South Florida where a large section of the population speaks Spanish, it wasn't hard to find birthday candles that spell out "Feliz Cumpleanos!" It was a huge hit!