Make the Cranberry Wine Sauce by combining the cranberries, wine and sugar in a small saucepan and placing over medium-high heat. Bring it to a boil, stir, then lower heat to a simmer, and let it cook for about 5-10 minutes, or until the cranberries have all popped. Transfer to a glass jar and cool completely. This can be done a few days in advance.
Preheat the oven to 400°F. If using a pizza stone, place it in the lower third of the oven.
In a large bowl, stir together the flour, sugar and salt. Using a pastry cutter or two forks, cut in the butter until the mixture resembles course crumbs. If you wish, this can also be done in a food processor. Slowly drizzle in the ice water, about a tablespoon at a time and toss until the dough just comes together. It will still be crumbly (take care not to make the dough too wet). Place in the center of a sheet of plastic wrap, using the wrap to bring it into the shape of a ball, wrapping as you go. Press it into a disk form and chill in the refrigerator for at least 30 minutes.
Place the dough between two sheets of parchment paper and roll out into a disk about 12 inches wide and 1/8 inch thick. It does not have to be perfect. Using a slotted spoon, arrange the cranberries and some sauce in the center of the disk. Sprinkle with walnuts and dollops of brie. Gently bring up the edges of the dough, folding and crimping a little along the way towards the center of the galette. Lightly brush the exposed dough with heavy cream or half and half.
Transfer the galette on the parchment to the pizza stone in the oven or on a baking sheet. Bake for about 25-30 minutes, or until the crust is golden brown. Remove from the oven when it is fully baked, and transfer to a cooling rack. When the filling has had some time to rest, slice the galette and enjoy, ideally with a glass of wine.