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

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

In a large mixing bowl, cream the butter and sugar together until light and fluffy, about 3-4 minutes.

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 ingredients, alternating with the milk, beginning and ending with the dry ingredients. Mix until just combined.

Divide the batter into two portions. Leave one portion plain and mix mini chocolate chips into the second portion. If desired, add gel food coloring to the chocolate chip batter to make colorful polka dots.

Spoon small dollops of the chocolate chip batter into the plain batter in each cake pan, creating 'polka dots' throughout the cake. Use a toothpick or skewer to swirl slightly, if desired.

Bake the cakes in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out clean.

Remove the cakes from the oven and allow them to cool in the pans for 10 minutes. Then transfer them to wire racks to cool completely.

To make the frosting, beat the softened butter until creamy. Gradually add the powdered sugar, heavy cream, and vanilla extract. Beat until light and fluffy, adjusting the consistency with more cream or powdered sugar if necessary.

Once the cakes are cool, spread a layer of frosting on top of one cake layer. Place the second layer on top and frost the top and sides of the cake.

Decorate the cake with sprinkles or additional polka dot designs using colored frosting, if desired.

Slice and serve your Vanilla Polka Dot Cake!