Between two pieces of parchment or wax paper, smash your peppermint puffs into small chunks. You can also pulse them in a blender.
Melt your chocolate over a double boiler. I don't have a double boiler, so I nestle a pyrex bowl over a small pot of boiling water (on high heat) and it works beautifully. Simply add all your chocolate to the bowl and stir it with a heat resistant spatula until it's melted through.
Stir in your peppermint extract until well combined.
Line a baking sheet with parchment paper or wax paper and pour the chocolate on top. Spread the chocolate to about 1/4 inch thick.
Sprinkle on your peppermint candy and pop it in the fridge or freezer until it's firm...usually about an hour. (I prefer freezer.)
When it's firm, peel it from the paper and give it a nice good drop back onto the pan. It should crack nicely. Crack any larger pieces by breaking them or dropping them again. Be careful not to handle it too much or it will start to melt in your hands.
It keeps best in the fridge until it's ready to be served.