Step 1 Combine the cream and chopped mint leaves in a saucepan. Bring to a gentle boil, then simmer on low heat for 10 minutes. Remove the pan from the heat and allow the mint leaves to steep 20 minutes. Strain and discard the mint leaves. Clean the saucepan and return the cream to the pan. Heat the cream to a gentle boil.
Step 2 Chop the chocolate into pieces no larger than one-fourth inch. Place it in a medium-sized bowl. Immediately pour the hot cream over the chocolate. Tap the bowl on the counter to allow the cream to reach all of the chocolate. Allow the mixture to sit for about 5 minutes.
Step 3Stir with a rubber spatula, beginning from the center of the bowl, until the chocolate and cream are thoroughly combined and no lumps of unmelted chocolate remain. Cover the bowl and refrigerate at least 6 hours, up to four days.