Pre-heat the oven to 325 degrees. Grease and flour 2 (8 or 9)-inch round pans. Sift together the flours and baking powder.
Cream the butter and sugar in a large mixer bowl until fluffy. Add the salt and vanilla and mix well. Add the eggs, scraping the sides of the bowl, and mix until light and fluffy. Add the flour mixture in 3 batches alternating with the milk, mixing after each addition and ending with the flour. Mix just until combined. Do not overmix.
Pour the batter into the prepared pans. Bake 30 to 35 minutes or until a toothpick inserted in the center comes out clean. Cool the cakes in the pans on wire racks for 15 minutes. Invert the cakes onto the racks and remove the pans. Let the cakes cool completely. Wrap and refrigerate before decorating.