Bake your cakes in a 6" round pan. You'll want the height of the cake. Cool completely. For easier handling, wrap and freeze them overnight. Torte the cakes.
Make a batch of your favorite frosting. I just made vanilla frosting for this cake.
Place the first cake layer on a cake board and then add a crumb coat. Refrigerate it for an hour.
Cut a second cake board down so that it's smaller than the diameter of the cake.
Pour your sprinkles out on to a cookie sheet with sides.
Using an offset spatula, frost just the sides of the cake.
Place the smaller, cut cake board on the top of the cake, then carefully lift the cake and roll it in the sprinkles. Use the two cake boards to hold on to the cake. This is why it's best if the cake is COLD! Make sure that all your sides are coated evenly.
Place the cake on a stand and remove the small cake board from the top.
Frost the top and then cover it in sprinkles by hand or with a spoon. Be sure to press down slightly to make sure that they stick to the frosting.