I have never baked a cake in a half sheet pan. I think my pans are 1" high.

How much cake batter do I use, what is the over temp. and how long do I bake?

To understand the size of my pans...just watch Buddy V on Cake Boss cook his sponge sheets.

I thought this would be an easy way to make layers.

Hi, I would suggest you look at a chart, there is one in every Wilton year book, to see how much batter they use for a 2'' layer and only add 1/2 that amount. I don't know how long to bake it though. I bake (convection oven) at the last zero on 300 degrees and I check very often to see if the cake is done. Usually when it pulls away from the sides is how I judge if it's done. I do like the idea of layers that size ( 1 inch high). Three layers would be a very nice size cake. Just try batter amounts and baking time and you'll soon know what's best for you and your oven. Good Luck.

I just baked a half sheet cake (12 x18x2) the other day. I use this WASC recipe
2 18 ounces boxed white cake mix
2 cups all purpose flour
2 cups granulated sugar
1 1/2 tsp salt
2 2/3 cups water
1/4 cup vegetable oil
2 tsp vanilla extract
2 tsp almond extract
2 cups sour cream
8 large egg whites

And it filled my sheet pan (don't know how many cups this is). I baked for about 50 mins at 325 w/ baking strips.