Preheat oven to 350 degrees F.

Mix first 5 dry ingredients in a greased 8" square baking pan. Make 3 depressions in dry ingredients - two small, one larger (see #3 in photo below). Pour vinegar in one depression, vanilla in the other and the vegetable oil in third larger depression. Pour water over all. Mix well until smooth.

Bake on middle rack of oven for 35 minutes. Check with toothpick to make sure it comes out clean. Cool. Top with your favorite frosting.