I did not read the recipe as closely as I should. It yields 21, so unless you want 42 cupcakes, I suggest you don't double the recipe...
But it was great to have so many cupcakes! Russell and Sam helped me, and I think they liked the part where they got to crush the peppermint candy canes the most.
I put the crushed bits of peppermint in the batter, the frosting and on top of the frosting. There was lots of goodness going around.
Recipe found here!
(Thanks, Sam, for the photos.)