Preheat the oven to 350 degrees F. Spray two 9-inch round cake pans with nonstick baking spray (or grease and flour them). I like to line them with rounds of parchment- it helps with getting the cake out of the pan intact.
In a medium bowl, whisk together the flour, baking powder and salt. In a larger bowl, use an electric mixer to cream the butter. Beat in the sugar and mix until fluffy, about 4 minutes. Beat in the eggs, one at a time. Add the dry ingredients in two parts- mix in half of the dry ingredients, then half of the milk, then the rest of the dry ingredients, and then the rest of the milk + vanilla. Be sure to scrape the sides of the bowl as you are mixing to incorporate all of the ingredients.
Divide the batter between the two prepared cake pans. Bake for about 30 minutes, or until a toothpick inserted into the center comes out clean. Let cool for 20 to 25 minutes, then run a knife along the edge of each pan and invert onto a rack to cool completely. Be sure to peel off the parchment paper and toss it!
Your cakes are ready to frost, or you can wrap them and keep them overnight until you are ready to frost your cake. I recommend using the Chocolate Frosting Recipe on this site for the Yellow Cake. It makes plenty of frosting for a two-layer cake.
Notes
Nutritional information is for cake only- not the frosting.