On a cake turntable, layer and crumb coat the cake on a cardboard cake round. Crumb coat, the freeze for 5 minutes.
Beat down the buttercream with a wooden spoon to get out any air bubbles and help make the buttercream more smooth.
Spread on a layer of buttercream, then use a cake scraper for smooth sides and edges. The jimmies will want to drag, so if they get in the way, you can use a more gentle touch with the cake scraper, or simply remove the sprinkle that is causing problems.
For the sprinkle border and top, use a sheet of parchment paper around the top half of the cake while the buttercream is still wet. Add the sprinkles to the bottom exposed half of the cake, and also on top. Freeze for 5 minutes, then carefully pull the parchment sheet off the cake.
Using a Wilton 1A piping tip, pipe dollops on top of the cake around the outside rim of the top. Carefully add on a few sliced strawberries. Enjoy!