I am making my first half sheet cake and I need a recipe to fit the pan. I usually make box cakes, so if anyone can give me a recipe from scratch and also if I use a box mix, how many boxes would I need and how long would I bake it for?
A 12x18 pan uses three Betty Crocker cake mixes. One cake mix will make two 8" rounds. So any scratch recipe that makes two 8" rounds is the same amount of batter as a cake mix.
I cite that I use Betty Crocker because different brands yield different amounts of batter. Reduce the oven temp (in a home oven, I bake at 325). Use baking strips. Some use flower nails instead of strips and some use flower nails in addition to baking strips. I just use the strips.
I never use a timer. My criteria for baking is "bake it until its done". When I can smell it, it's done. (The only time my timer gets used is when I give the grandkids a 10 minute time out. "When gramma's buzzer goes off, you can get up and go play!")
You're going to do your first scratch cake on a 12x18 sheet? Wow, you're braver than me! I'd need to practice on a little cake first!