Preheat your oven to 350°F (175°C) and grease two 9-inch round cake pans.
In a bowl, whisk together the flour, baking powder, and salt.
In a separate bowl, cream the butter and sugar until light and fluffy.
Add the eggs one at a time, mixing well after each addition.
Stir in the vanilla extract.
Gradually add the dry ingredients to the wet mixture, alternating with milk.
Fold in the rainbow sprinkles gently.
Divide the batter evenly between the prepared pans.
Bake for 30-35 minutes or until a toothpick comes out clean.
Let the cakes cool in the pans for 10 minutes, then transfer to wire racks to cool completely.
Frost the cooled cakes with your choice of frosting and sprinkle more on top.