Preheat oven to 350 and spray two 9-inch cake pans liberally with cooking spray, or grease and flour. (Can also use a 9x13-inch pan or line 24 muffin tins with paper liners for cupcakes).

Combine sugar and butter in a large bowl and cream together with an electric mixer.

In a medium-sized bowl, stir together the flour, baking powder, and salt with a spoon. In a separate bowl, stir together the eggs, milk, and vanilla until well combined.

Add half of the wet mixture and the flour mixture to the creamed butter and mix until well combined. Add the remaining and continue mixing until fully blended and smooth, about 2 to 3 minutes.

If you want to add sprinkles, gently stir them using a spoon, once the cake batter is fully blended.

Divide the cake mix evenly among the two cake pans. Bake for 30 to 35 minutes, or until lightly browned and center springs back when lightly pressed. Remove from oven and allow to cool in pans for 10 minutes before turning out to cool completely.

In a large bowl, cream the butter and about 1 cup of confectioner's sugar with an electric mixer until light and fluffy. Add the butter flavoring, half of the milk, and the remaining sugar, and beat again until smooth and creamy, scraping down the sides and adding a little extra milk if needed.

Ice the cooled cake (see photos and instructions in this post if needed) and enjoy!