This cake is the absolute perfect base for all of your topping, swirl, and add-in dreams. It's moist, just sweet enough, and has a great crumb—plus it's quick to whip up. Most importantly, though, it is the ultimate base for any flavor combination, topping, or general dessert experimentation you want to try. Put on your lab coat—er, apron—and get to playing! —Catherine Lamb
In a medium bowl, sift together the flour, baking powder, and salt. Set aside.
In a large bowl, or in a stand mixer, beat the butter and sugar together until light and fluffy, 4 to 5 minutes. Do not skimp on this step!
Beat in the eggs, one at a time, scraping down the sides and making sure batter is fully combined after each addition. Add the vanilla and beat to combine.
Add one-third of the dry ingredients, beat to combine, then add half of the buttermilk and mix again. Alternate between dry and wet ingredients, starting and ending with the dry, until everything is just combined.
Preheat the oven to 350° F. Line a 9 x 9-inch square pan (or a loaf pan, or a 9-inch circular pan) with parchment paper, then butter or spray the paper.
Pour the batter into the prepared pan and smooth it out with a spatula. Bake for 45 minutes to 1 hour, or until a toothpick inserted in the center comes out clean.