There's enough icing to pipe/spread/scoop about 2.5 Tbs of icing on each cupcake. Fit a piping bag with your favorite tip and pipe the cupcakes. Or use a large cookie scoop, 2-3 Tbs, to place a scoop on top of the cupcake. Invert the cupcake into sprinkles
and roll the icing into the sprinkles, gently pressing to shape the dome.