Preheat your oven to 350°F (175°C).

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

In a large mixing bowl, cream together butter and sugar until light and fluffy.

Add eggs one at a time, mixing well after each addition, then stir in vanilla extract.

Gradually add the dry ingredients to the wet mixture, alternating with milk. Mix until just combined.

Add blue food coloring to the batter until desired shade is achieved.

Divide the batter between two prepared 9-inch round cake pans.

Bake for 25-30 minutes or until a toothpick inserted comes out clean.

Let the cakes cool in the pans for 10 minutes, then transfer to a wire rack to cool completely.

For the frosting, beat butter until creamy, then gradually add powdered sugar and milk until smooth.

Add vanilla extract and blue food coloring to the frosting until desired shade is achieved.

Frost the top of one cake layer, place the second layer on top, and frost the top and sides of the cake.

Decorate with edible pearls or sprinkles.