Preheat the oven to 350 degrees. Line a muffin tin with 12 cupcake liners. I used half blue and half pink to match the cupcakes.
In a medium bowl combine the flour, baking powder, and salt. Set aside.
In a large bowl cream together the butter and sugar. Add the eggs and beat until smooth. Stir in the vanilla.
Add in half the flour mixture and stir well. Mix in the milk and stir until combined. Stir in the remaining flour mixture.
Divide the batter into two bowls. Color one pin and the other blue.
Pour into cupcake liners, filling 2/3 of the way full. Bake for 20-25 minutes or until a toothpick inserted into the center comes out clean.
Cool on a wire rack.
Meanwhile, beat the butter in a large bowl. Add the powdered sugar 1/2 cup at a time until desired consistency is reached. Stir in the vanilla and milk and beat until smooth.
Add in brown food coloring.
Place a thin layer of brown frosting on top of each cupcake. Place remaining frosting in a piping bag with a small tip. Pipe it on in a circle, making a nest. Fill each nest with 3 chocolate eggs.