In a microwave safe bowl, combined the chopped chocolate and cocoa butter. Heat on high in 30 second increments, stirring until smooth. Alternatively, you can melt the chocolate on the stove-top double-boiler style. Stir in the peppermint extract
If using cookie cutters, set them on a parchment-lined baking sheet and spoon a little of the melted chocolate into each. Use a toothpick or other small pointed utensil to push the chocolate into the corners of each cookie cutter. If using silicone mini muffin cups, use about 24 and divide the chocolate between them (you could also use 12 larger muffin cups). Freeze the chocolate layer for at least 30 minutes to set.
You can also line an 8x8 pan with parchment and simply pour the chocolate in. Freeze before continuing to the next step.
White Chocolate Layer:
In a microwave safe bowl, combined the cocoa butter and coconut oil. Heat on high in 30 second increments, stirring until smooth. Alternatively, you can melt them on the stove-top double-boiler style. Whisk in the powdered sweetener and peppermint extract until smooth.
Divide the mixture among the cookie cutters or muffin cups or spread over the chocolate layer in the pan. Freeze about 10 to 20 minutes, until just starting to set, then sprinkle with crushed peppermint candies, if using. Return to the freezer until completely set, another 20 minutes or so.
Store in the refrigerator.
Notes
How many pieces you get depends on the size you are making them. I used small holiday cookie cutters from Sur La Table (about 2 inches tall) as well as mini muffin cups. The holiday shapes were bigger than the cups, so a single shape is a serving, whereas two of the cups is a serving.