I have a cake recipe (ingredient list below) which makes a relatively light cake, very much like traditional cupcakes. However, I prefer a sturdier, denser cake. I tried replacing 1/4 cup of the all-purpose flour with whole wheat flour, and was able to achieve the desired density. Unfortunately, it had an adverse effect on the flavor and color of the cake. I may try the same trick with spelt flour instead of the whole wheat, and see what happens. I've also been wondering if I could simply increase the amount of all-purpose flour and/or decrease the water, or possibly just reduce the baking soda and/or vinegar. Does anyone here have an opinion on what is the best method for increasing the density of a cake? Thanks!

1 1/2 cups unbleached all-purpose flour
1 cup sugar
1 teaspoon baking soda
1/2 teaspoon salt
1/2 cup vegetable oil
1 cup water
1 tablespoon vanilla extract
1 tablespoon vinegar