An extremely rich, dark chocolate concoction with the consistency and taste of a truffle. It sounds (and tastes!) much more complex than it is, and the result is something that will wow the crowd. This is best served with a topping to offset the intensity of the chocolate. Fresh whipping cream is my choice, but for a potluck fresh berries may be a better pick because the cream may fall unless it is kept well-chilled. Even fresh fruit like sliced bananas would be an interesting twist and complement the chocolate well. cream-cheese frosting or fruit dip may be too sweet for your taste, but try it and see!
The liqueur does not entirely bake off, so if alcohol is an issue try substituting another liquid. Water will give a more basic chocolate flavor, while coffee would add a touch of mocha. A chocolate-compatible fruit juice such as orange, cherry or pomegranate would do interesting things as well. Use water and add 3/4 tsp peppermint extract for a chocolate-mint flavor.
If you use a spring-form cake pan, either wrap the outside really well with tin foil to prevent the water bath from leaking in (this is tricky to really make water-tight though), or set a large pan of water on the rack directly below the cake pan (as close as possible). The bain-marie adds moisture so that the surface of the cake does not dry out and crack during the long baking.
1/2 cup Grand Marnier liqueur (see note above for substitutions)
1 cup salted butter (or unsalted + 1/4 tsp salt)
3/4 cup white sugar
4 ounces unsweetened chocolate
14 ounces semi-sweet chocolate
3 large eggs
3 egg whites
Preheat the oven to 300 degrees F.
start a pot of water to boil. You’ll be either setting the cake pan in a larger pan filled with boiling water (preferred), or if using a springform pan, setting a pan of boiling water directly underneath it. Make sure you boil enough water to give you a 1″ deep “bath” (bain-marie).
Line the bottom of a 10″ cake pan with parchment and grease it and the sides lightly. See notes above for using a springform pan. You can make mini-cakes with liners in a cupcake tin, but reduce cooking time to 40 minutes.
Place the chocolate pieces in a large glass mixing bowl in the microwave for 30 seconds on high. Stir, then microwave for an additional 20 seconds. Continue stirring until smooth, cooking for an addition 10 seconds at a time if the pieces are not melting after stirring for one minute.
Combine liqueur (or substitute) and sugar in a small saucepan and stir constantly over medium-low heat until the liquid is clear and sugar is dissolved. Set aside.
Soften butter (microwave 5 seconds at a time on high, turning sticks 1/4 turn after each interval until very soft)
stir butter well into chocolate until smooth
stir sugared liquid into mixture until smooth
beat eggs in a separate bowl. Slowly add about 1 cup (doesn’t need to be exact) of the chocolate mixture to the eggs while stirring briskly. Then stir the egg mixture back into the main bowl, continuing to stir. This is called “tempering.” You are bringing the eggs up to temperature before adding them to the hot liquid. This prevents bits of cooked egg from spoiling the texture of the cake.
Pour the mixture into the prepared cake pan. Fill the bain-marie with boiling water 1/2″ up the sides.
Bake for 45 minutes. the center will still look wet when you pull it out, but it will continue baking for a while even after you’ve removed it from the oven and will set up when chilled.
Leave the cake in the pan to chill. Let cool at room temperature for 30 minutes, then chill for at least 4 hours or overnight in the refrigerator to set.
To remove from pan, let the bottom rest in hot water for 2 minutes. Then use a knife dipped in hot water to run around the edge and loosen. turn over on a serving dish and let loosen/fall. Cut with a sharp knife dipped in hot water between slices. See notes above for toppings/garnish. Store in fridge up to 1 week.