Preheat an oven to 350 degrees F (175 degrees C). Grease 2 8-inch cake pans.
Place the butter and sugar into a mixing bowl, and mash together with a wooden spoon until the mixture is creamy and thoroughly combined. In a separate bowl, beat the eggs, and pour into the butter mixture. Stir until combined.
Sift the flour and baking powder together in a bowl, and lightly stir into the butter mixture. Pour half the batter into each prepared cake pan.
Bake in the preheated oven until a toothpick inserted into the middle of a cake comes out clean, 20 to 25 minutes. Cool in pans for 10 minutes before removing to finish cooling on wire racks.