For easy removal, grease the bottom of the tart pan with butter or line the bottom with parchment paper. Roll the dough out, transfer to the tart pan, trim the excess dough and prick all over with a fork. Refrigerate for 30 minutes.
Preheat oven to 350 degrees F. Place the tart in the oven for 20 minutes, or until golden. Remove from the oven and set aside on the serving plate.
Meanwhile, bring the heavy cream to a boil, then pour over the chocolate. Let stand for 2 minutes. Stir gently until the mixture becomes smooth and dark.
Pour chocolate ganache into crust to the top. Cool completely. If you made this dessert during the hot summer, it will be the best to refrigerate it. If it’s not too hot in your kitchen, let it stand on the counter top at room temperature.