Here is a basic recipe for cornbread - probably the one found on the side of a cornmeal container. They call for a 1:1 cornmeal to flour ratio, but I prefer 2:1, so I use 1 1/3 c cornmeal to 2/3 c flour. But this is the original recipe, which is for an 8x8 pan (a 9x9 pan can be used, for a thinner bread). I would always double it, and bake in a 9x13 pan.
1 c unbleached flour
1 c cornbread
4 tsp baking powder
3/4 tsp salt
1 tb sugar (or more; I'm not a fan of sweet cornbread)
1 c buttermilk (or milk, but I like the BM)
2 eggs, beaten
1/4 c melted butter
Preheat oven to 425°. Grease an 8x8 pan (9x13 to double the recipe).
Whisk the dry ingredients together in a mixing bowl. Make a well, and pour in the buttermilk and eggs. Whisk briefly, then add the melted butter and whisk it in. Pour batter into pan and level out.
Bake 22-25 min., or until bread tests done with a toothpick.