Preheat your oven to 350°F (175°C) and grease two 8-inch round cake pans.
In a mixing bowl, cream together the softened butter and granulated sugar until fluffy.
Add the eggs one at a time, mixing well after each addition.
Stir in the vanilla extract and mix until combined.
In a separate bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the butter mixture, alternating with milk, and mix until smooth.
If using, divide the batter into separate bowls and add food coloring to create different colors.
Pour the batter into the prepared pans, filling each about halfway.
Bake in the preheated oven for 25-30 minutes, or until a toothpick comes out clean.
Allow the cakes to cool in the pans for 10 minutes, then transfer to wire racks to cool completely.