Preheat oven to 350°.
Whisk together flour, baking powder, and salt. Set aside.
In a medium bowl, cream together the butter and sugar with a hand mixer until cute & fluffy, 2 minutes.
Add egg white, vanilla, milk, and mayo, and whip that hoe for 1 minute.
Switch to a wooden spoon and add the dry ingredients until just combined and smooth, do not over-mix.
Stir in the sprinkles. Again, careful of over-mixing because sometimes these colors run.
Grease a 1 quart Pyrex and dust it evenly with flour. Pour in batter and bake for 35-40 minutes, or until the middle is perked up all the way like a plump bosom. A toothpick inserted should come out clean.
While the cake is baking, beat together frosting ingredients.
Allow cake to cool completely before frosting. Garnish with all the sprinkles you want!
GRAB THE POPPERS AND LET THE GOOD TIMES ROLL!!!