Coconut cream is best in this recipe. If using full-fat coconut milk, do your best to scoop out only the cream and reserve the leftover liquid in the bottom of the can for other uses (like smoothies), anduse 1/2 cup less chocolate*. Otherwise, use coconut cream and add the full amount of chocolate.
Melt chocolate in the microwave in 30 second increments or over a double boiler until creamy and smooth (be careful not to cook past melting point).
Add coconut cream to a medium or large mixing bowl along with melted chocolate and whisk thoroughly to combine. Add peppermint oil and mix once more. Start with 1/8 tsp, then graduate up to 1/4 tsp depending on desired mintiness (amounts as original recipe is written // start with lesser end of range and increase as desired).
Cover and set mixture in the refrigerator to chill fully - about 4 hours. You'll know it's ready to whip when the mixture no longer sloshes around when tipped side to side.
Once chilled and semi-firm, whip until creamy and smooth with a hand mixer, scraping down sides as needed.
At this point you can either transfer to a piping bag or large plastic bag (with the corner clipped off) to "pipe" into dishes. Otherwise, use a spoon to divide between 3-4 serving ramekins (amount as original recipe is written // adjust if altering batch size) or short drinking glasses and cover with plastic wrap.
Enjoy as is, or chill for 30 more minutes to allow the mousse to firm up even more (or chill overnight).
To serve, top with coconut whipped cream, crushed peppermint, and/or chocolate shavings or cocoa or cacao powder.
Leftovers will keep in the fridge up to 3-4 days, though best when fresh. I haven't tried freezing this recipe and wouldn't recommend it.
*Nutrition information is a rough estimate calculated using COCONUT CREAM for the mouse and does not include any additional coconut whipped cream or other toppings. *Prep time does not include chilling.