You can whip this show-stopper up in the time it takes to make rice krispie treats! Make it a couple hours ahead and leave it out on your counter (or bring it to room temp if you bake it ahead of time).
For an even more hands-off approach, you can even buy a chocolate cookie crust in the baking aisle, with little-to-no sacrifice of flavor!
1 1/2 cups chocolate graham cracker crumbs
3/4 stick (6 tablespoons) unsalted butter, melted and cooled completely
1 tablespoon ground coffee
1/3 cup heavy cream
1/2 lb fine-quality bittersweet chocolate coarsely chopped-- or use chips
3/4 stick stick (6 tablespoons) unsalted butter, cut into 1/2-inch cubes
2 large eggs, lightly beaten
1/4 cup granulated sugar
1/4 teaspoon salt
1 teaspoon pure vanilla paste (or extract)
For Cardamom Whipped Cream:
1 pint whipping cream
1 tablespoon cardamom simple syrup
Fresh Berries (optional)
Put oven rack in middle position and preheat oven to 350°F. Lightly grease a pie plate. Stir together ground graham crackers and butter in a bowl until combined, then pat mixture evenly onto bottom and sides of plate. Bake until crust is slightly puffed, about 10 minutes, then cool completely in pan on a rack, about 15 minutes. Leave oven on. Make filling while crust cools:
Combine coffee and cream in a saucepan. Bring to a simmer, then let coffee steep in the cream. Meanwhile, melt chocolate and butter in a double-boiler over medium-low heat, stirring until smooth. Whisk together eggs, sugar, salt, and vanilla in a bowl. Set strainer over egg mixture, then pour cream through, and mix thoroughly. Whisk chocolate mixture into egg mixture until combined well.
Assemble and bake tart:
Pour filling into cooled crust and rap pan once on counter to eliminate any air bubbles. Bake until filling 1 inch from edge is set and slightly puffed but center trembles slightly when pan is gently shaken, 20 to 25 minutes. (Center will continue to set as it cools.) Cool tart completely in pan on a rack, about 2 hours. Chill if not serving the same day.
Bring tart to room temp. Whip cream to soft peaks, then add the cardamom syrup. Continue whipping to firm peaks. Cut slice of chocolate tart, then add a dollop of whipped cream. Vow to run 10 miles tomorrow, then dig in!