You will need a half-sheet pan measuring 18x13x1 inches for this recipe. For small-batch baking, cut the recipe in half and use a quarter sheet pan (13x9x1 inches). To make a half recipe of this sheet cake with buttermilk, in the recipe card below, change the number of servings to 12. The ingredient amounts will recalculate. Prepare as directed, baking for 9-11 minutes or until a cake tester inserted in the center comes out clean.