Place a 12 by 16-inch piece of parchment paper on the counter and dust it lightly with cocoa powder. Turn the dough out onto the parchment and dust the top with cocoa powder. Cover the dough with a second piece of parchment. Roll the dough out to a 1/8-inch thickness. Cut the dough into rounds with a 1 3/4-inch cutter.
Place chocolate in a small glass bowl. Microwave on medium heat for 30 seconds. Remove from the microwave and stir. (Do this even if it looks like the chocolate isn't melting.) Repeat until the chocolate is smooth. Stir in the coconut oil and two to three drops peppermint oils into melted chocolate. Stir gently until coconut oil melts. Taste. Add more peppermint oil if needed.