Preheat your oven to 350°F (175°C) and prepare two 9-inch round cake pans by greasing and flouring them.
In a large bowl, whisk together flour, baking powder, and salt.
In a separate bowl, cream the softened butter and sugar until light and fluffy.
Add eggs one at a time, mixing well after each addition.
Stir in vanilla extract, blending until smooth.
Gradually add the dry ingredients to the wet mixture, alternating with milk.
Fold in the rainbow sprinkles gently to avoid breaking them.
Evenly distribute the batter into the prepared pans.
Bake in the preheated oven for 30-35 minutes or until a toothpick comes out clean.
Let the cakes cool in the pans for 10 minutes before transferring to wire racks to cool completely.