Beat egg in large mixing bowl with an electric beater for 2 to 3 minutes. Do not skip this step! Add sugar, and continue beating for another 4-5 minutes until light and fluffy. Add vanilla and stir on low until just combined. In a separate bowl, sift together dry ingredients. Add to eggs and sugar on low speed until just combined. In a saucepan, heat milk and butter on low heat just until butter is melted. Add to batter, beat just until combined.

Divide the batter into 2 separate bowls. Colour one bowl green and the other bowl blue. Line a round cake pan with parchment paper. Drizzle colored cake batter, alternating colors into the pan until you use all the batter. Tap the pan on the counter a few times to remove air bubbles. Preheat oven at 170-degree centigrade and bake for 30 minutes or until a toothpick inserted comes out clean. Cool the cake completely and demold it.

Now make another cake batter by doubling the recipe. Colour the cake batter yellow. Line a loaf pan with parchment paper. Pour a thin layer of cake batter into the loaf pan. Arrange the stars in a single row down the center of the pan, piping batter into the pan as needed to keep the star pieces straight. Pour the remaining batter into the pan and on top of the stars. Bake for 35 to 40 minutes at 170-degrees centigrade.

Let the cake cool completely. Remove from pan. Drizzle some sugar syrup on top of the cake and on all the sides as well. Cover the cake with whipped cream. Smooth the icing as much as possible. Decorate with some sprinklers. And the cake is ready to surprise your special one.