It occurred to me, after I had made these, that she intended these to be made with peppermint candies, not peppermint extract. Actually, I didn't realize it at all; Jake clued me in to the red and white swirled chunks in her drawing. Whoops. Hope she likes these anyway.
I melted dark chocolate in a double boiler, stirred in some pure peppermint extract, and poured it onto a parchment to harden. Then I cracked the chocolate into rough pieces when it was completed cooled.