Start at least 8 hours ahead. Combine 3 tablespoons mint leaves with 1 cup of heavy cream in an airtight container. Keep in the fridge for 8 – 12 hours.
In a medium bowl, add the cocoa powder and sugar. Whisk in 2 tablespoons of heavy cream until smooth with no lumps. Slowly whisk in the rest of the cream. Cover with plastic wrap and keep in the fridge for 1 hour.
In a large Ziploc bag, place in the thin mints cookies. Squeeze out all the air and seal tightly. Crush the cookies with a heavy object, like a rolling pin. Crush until the cookies are the size of peas. It is ok if some are bigger and some are smaller. Set aside.
For the mint cream, strain the cream through a sieve to a large mixing bowl. Press the mint leaves to extract as much as possible. Discard the leaves.
In an electric mixer fitted with a whisk attachment, whip the cream and sugar until foamy. Add ½ tablespoon minced mint leaves. Taste and add more sugar and mint if needed. Whip until stiff peak forms. Transfer the whipped cream to a medium bowl. Cover with plastic wrap and keep in the fridge.
In another large mixing bowl with an electric mixer fitted with a whisk attachment, add the chocolate heavy cream and whip until stiff peak forms.
To assemble, place a thin layer of crushed cookies at the bottom of 4 small mason jars or desired containers. Add a layer of chocolate whipped cream, and then add another layer of cookies. Next is to add a layer of mint whipped cream, and a layer of cookies. Repeat with the chocolate whipped cream. Finally, top with more cookies. Cover and keep in the fridge for 4 – 8 hours. Reserve about 1 cup of mint whipped cream and keep in the fridge.
Before serving, top each mason jar with a dollop of mint whipped cream and a fresh mint. Serve.