Preheat oven to 350ºF.

In a medium bowl, mix flour, baking powder and salt.

In a large bowl, use a hand mixer to beat butter, shortening and sugar until light and fluffy.

Beat in egg whites one at a time, mixing and scraping after each addition. Mix in extracts.

On low speed, alternate adding the flour mixture and milk to the butter mixture, beginning and ending with the flour mixture.

Spray all 15 pans and divide batter evenly between them. Bake for 20 minutes.

Roll out yellow fondant and cut out stars.

Frost and stack 3 cakes on top of a cake board. Make sure to pipe a few dollops of frosting on the cake board before placing the first cake.

Repeat step 2 three more times so that you have 4 frosted stacks on their own cake boards.

Use 2 of the 3 remaining cakes to make a small frosted stack on a cake board. Place the last cake on its own cake board and then frost it with blue frosting.

Press a dowel into a round Styrofoam base to create a foundation for the cakes.

Position a cake stack so that the hole in the middle of the cake board is lined up with the dowel and then guide the cake down to the base. Cut and place 4 large straws into the cake to create more support.

Continue stacking cakes, ending with the small stack and the blue cake.

Use a #10 tip to pipe blue frosting in thick wavy lines. Place fondant stars onto the sides of the blue cake.

Use a star tip to pipe yellow frosting into draping 'U' shapes connecting each star.

Pipe 15 small yellow dollops around the outside of the blue cake and then stick a candle into each dollop.