Heat oven to 350° F.
Coat a two-piece tube cake pan [or a 9x13 pan] with baking spray or grease and flour well.
Separate the eggs, reserving the yolks for later in the process.
Whip the egg whites with the pinch of salt until soft peaks are formed.
Set aside the whipped egg whites.
In a small bowl combine flour and baking powder.
Set aside the mixture.
In a clean bowl or in a stand mixer, cream the butter and sugar.
Add the egg yolks to the butter and sugar and mix until fully incoporated.
Add the vanilla to the mixture and stir until combined.
In alternating batches, add the flour mixture and milk, stirring until incorporated.
Add the sprinkles or chopped chocolate and mix until just combined.
With a spatula, by hand, incorporate the whipped egg whites.
Bake for 40-45 minutes, or until a skewer comes out clean.
Cool the cake on a wire rack for 10 minutes [or cool completely if using a rectangular pan.]
Shimmy a butter knife around the outside circumference of the tube pan, and remove the cake from the outside tube pan.
Shimmy a butter knife below the bottom of the cake and around the inside circumference of the pan.
Invert the cake [bottom's up!] onto a serving dish.
Allow to cool completely before icing and decorating. Cake may be wrapped and stored for up to 24 hours on the counter before icing and serving.