Preheat oven to 350°F.
In a food processor puree the Oreo cookies until they are a fine crumble.
Melt the butter and add it to the cookie crumbs. Stir until the crumbs are moist and then press the mixture into a 9-inch tart pan covering the bottom and up the sides.
Bake the tart crust for 7-9 minutes or until crust is firm.
Let the tart cool to room temperature them place it in the freezer for 30 minutes.
After 30 minutes remove the crust from the freezer and spread softened mint chocolate chip ice cream over it evenly filling the tart about halfway to 3/4 of the way up.
Place the tart back in the freezer while you make the ganache.
Heat the heavy cream in the microwave for 1-2 minutes or until it begins to bubble.
Remove and pour over the chocolate immediately, stirring until the mixture is smooth.
Keep stirring to let the mixture cool slightly but not too long because you want the ganache to pour easily.
Remove the tart from the freezer and pour the ganache over it using a knife to smooth out the top.
Place the tart back in the freezer until ready to serve or at least 30 minutes.