Special equipment: a wooden dowel 3 feet long and 1 inch in diameter, a pair of sharp shears or small saw for cutting dowel, a digital or chocolate tempering thermometer and 2 disposable pastry bags
Preheat the oven to 300 degrees F.
For the pistachio creme brulee: Put the egg yolks in a medium heatproof bowl. In a medium saucepan, combine the heavy cream and sugar and bring to a boil over high heat. At the boil, remove the saucepan from the heat and slowly whisk the hot cream mixture into the egg yolks. Mix the pistachio paste into the hot cream/yolk mixture, blending thoroughly. Strain the mixture.
Pour the creme brulee mixture into a 9-inch cake pan. Place the cake pan in a large roasting pan or baking dish and carefully pour hot water into the pan around it, halfway up the sides of the cake pan, to make a water bath. Bake until set and no longer liquid in the center, 45 minutes to 1 hour. Check by jiggling the pan very gently; the creme brulee should tremble just slightly. Remove the roasting pan from the oven (but leave the oven on for the cheesecake), remove the cake pan from the water bath, cool the brulee to room temperature and then refrigerate for several hours until cold.
For the mascarpone cheesecake: In the bowl of a heavy-duty mixer fitted with the paddle attachment, beat the cream cheese and sugar on medium speed until smooth. Add the mascarpone and beat until smooth. Beat in the whole eggs one at a time, scraping down the bowl and beater between additions. Beat in the egg yolks, followed by the vanilla.
Pour the mixture into a 9-inch cake pan. Place the cake pan in a large roasting pan or baking dish and carefully pour hot water into the pan around it, halfway up the sides of the cake pan, to make a water bath. Bake until the cheesecake is set and no longer liquid in the center, 30 to 45 minutes. Check by jiggling the pan very gently; the cheesecake should tremble just slightly. Turn off the oven and leave the door open. Cool the cheesecake in the oven for about 30 minutes, then refrigerate until firm--preferably overnight.
For the chocolate tree trunks: Cut the 3-foot wooden dowel into twelve 3-inch lengths. Cut twelve 3-inch squares of aluminum foil. Lay a piece of dowel parallel to one of the edges of a foil square and roll the foil around the dowel. Repeat with the remaining dowels and foil.
Cut twelve 8-inch squares of plastic wrap. Hold a foil-wrapped dowel by one end. Place the opposite end of the dowel in the center of a square of plastic wrap. Hold the dowel and plastic wrap up so that the plastic drapes over the dowel. Gather the corners of the plastic wrap to enclose the dowel in the plastic. There will be a lot of wrinkles in the plastic. This will give texture to the tree trunks. Twist the ends of the plastic wrap together, or secure the ends of the plastic wrap with tape. Repeat with the remaining dowels and plastic.
To temper the chocolate, melt 24 ounces of the chocolate in a metal bowl set over a pan of simmering water fitted with a digital or chocolate tempering thermometer. Heat to 115 to 120 degrees F.
Remove the bowl of chocolate from the heat and add the remaining 8 ounces of chocolate. Stir until all the added chocolate has melted. The temperature of the chocolate should be below 86 degrees F. If not, allow the chocolate to continue to cool, stirring frequently, until it reaches 85 to 86 degrees F.
Place the bowl of chocolate over the simmering water again and reheat for a few seconds at a time, stirring well, until the temperature has risen to 87 to 91 degrees F. (Do not allow the temperature of the chocolate to exceed 91 degrees F, or you will have to repeat the procedure from the beginning.) Wipe any moisture from the underside of the bowl before proceeding.
Use a pastry brush to brush a coating of tempered chocolate onto the bottoms and up the sides of each dowel. Stand the dowels upright on a piece of parchment paper or aluminum foil and allow to stand until the chocolate is just set. Apply a second coating of tempered chocolate for added strength. Set aside for 1 to 2 hours, or overnight.
When ready to unmold, place the chocolate-coated dowels in the refrigerator for 10 to 15 minutes. Undo the plastic wrap and remove the dowel from each. Hold each tree trunk securely in one hand (wear gloves to avoid fingerprints) and carefully remove the plastic wrap from the insides of the tree trunks.
To assemble: Place the pistachio creme brulee mixture into a disposable pastry bag and snip a small opening. Pipe about a tablespoon of the mixture into the bottom of each hollow tree trunk.
Use a spoon to scrape off the top skin of the cheesecake and carefully scoop the soft cheesecake center into a disposable pastry bag and snip a medium-sized opening. Pipe the cheesecake mixture on top of the pistachio creme brulee in the hollow tree trunks, filling as full as desired.
Garnish each with a maraschino cherry and chopped toasted nuts if desired.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.