Preheat your oven to 350°F (175°C). Grease and line two 8-inch round cake pans with parchment paper.

In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.

In a large bowl, beat the butter and sugar together until light and fluffy. Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

Add the dry ingredients to the wet ingredients in three additions, alternating with the milk, starting and ending with the dry ingredients. Mix until just combined.

Divide the batter into several bowls, based on how many colors you want for the polka dots. Add a small amount of gel food coloring to each bowl and mix until evenly colored.

Using a small cookie scoop or a melon baller, drop small dollops of the colored batter onto a parchment-lined baking sheet. Bake the dollops for 5-7 minutes or until set. Let cool completely.

Pour a thin layer of uncolored batter into the prepared cake pans. Arrange the baked polka dot dollops in the batter, ensuring even spacing. Pour the remaining batter over the dollops to cover them completely.

Bake the cakes for 30-35 minutes, or until a toothpick inserted into the center comes out clean. Allow the cakes to cool completely on a wire rack.

Level the cooled cakes if necessary for even stacking. Apply a thin crumb coat of buttercream frosting to seal in any crumbs.

Roll out white fondant on a clean surface dusted with powdered sugar. Cover the cake with the fondant, smoothing it out with your hands or a fondant smoother.

Roll out colored fondant and cut small circles to create polka dots. Attach the polka dots to the fondant-covered cake using a small amount of water or edible glue.

Create a fondant ribbon by rolling out colored fondant into a long, thin strip. Wrap it around the base of the cake. Form a bow by shaping fondant into loops and securing them together with edible glue or water. Attach the bow to the cake.

Refrigerate the finished cake until ready to serve. Allow it to come to room temperature before slicing.