1. Take one stick of butter at room temperature. Beat for 30 seconds, add 3/4 cup of white granulated sugar and beat for additional 30 seconds. 

2. Add 2 tsp of vanilla extract and two eggs, and beat for one minute.

3. Add 1/2 cup of buttermilk, and beat for 30 seconds. 

4. Sift 1 1/4 cup of All-Purpose Flour, 1 tsp baking powder, 1/4 tsp salt into the cake batter. Beat for one additional minute to make a smooth batter. 

5. Add 1/4 cup of rainbow sprinkles into the batter and gently fold in with a spatula. 

6. Transfer the batter to a 6′ by 4 ‘ round greased and lined pan or 8′ by 2’ round pan. Bake the cake at 325 F for 40 minutes or until the toothpick inserted into the middle of the cake comes clean. Cool the cake in a wire rack and flip it over. 

7. Cut the top of the cake and into two layers. Optional trimming of the sides of the cake to make the rainbow sprinkles stand out. 

8. For Buttercream frosting, take two sticks of room temperature butter (1 cup) and beat t on a low speed. Add 4 cups of powdered sugar, 1/2 cup at a time. Beat it on alow speed for about 5 minutes.

9. While beating, add the rest of the powdered sugar in the 5 minutes duration and add 1 tsp of vanilla extract. The cream incorporates the air and starts to become fluffy and more creamy.

10. Fill the piping bag with cream and layer the cakes and decorate with cream in between the cake layers. The piping tip used in this video is 4 B.