| 1 | Preheat the oven to 350°F. |
| 2 | Butter and flour a 10-inch tart pan with a removable bottom. |
| 3 | In a medium saucepan over moderate heat, combine the butter and the sugars. |
| 4 | Cook, stirring constantly, until the butter is melted, 4 to 6 minutes. |
| 5 | In the bowl of a food processor, combine the bittersweet and unsweetened chocolate and process until finely chopped, 15 to 20 seconds. |
| 6 | Add the hot butter-sugar mixture and process for 15 more seconds. |
| 7 | Scrape the sides of the bowl and add the eggs and vanilla. |
| 8 | Process to combine, about 10 seconds. |
| 9 | Add the flour, salt, walnuts, and grand marnier. |
| 10 | Pulse briefly 10 times, just to mix. |
| 11 | Spread the batter evenly into the prepared pan and sprinkle the top with chocolate chips. |
| 12 | Bake 25 to 30 minutes; a toothpick inserted near the center will come out moist. |
| 13 | Do not overbake. |
| 14 | Remove the sides of the pan and cool on a wire rack. |
| 15 | Cut into wedges and serve. |
| 16 | Serves 6 to Recipe from celebrity gourmet cook-off |
