Preheat oven to 350.
Place a baking sheet on bottom rack to catch any drippings.
Butter an 8-inch springform pan; set aside.
Place the cranberries, sugar, and water in a small saucepan and bring to a simmer.
Continue to simmer for 10 minutes.
Press brown sugar on bottom of previously prepared sprinform pan.
Drizzle melted butter over brown sugar.
Spread prepared cranberry sauce on top of brown sugar.
Lightly flour your working area and slightly roll out thawed pastry sheet.
Place springform pan over pastry sheet; using a knife cut around the pan.
Take the round cut-out pastry sheet and place over cranberry sauce. Pull on the sides of dough so that it completely covers the cranberries.
Brush with egg and sprinkle with raw sugar.
Cut a few slits in the dough.
Bake on middle rack for 18 to 20 minutes, or until golden brown.
Remove from oven and let cool for 10 minutes.
Run a knife around the edges and carefully snap open the springform pan.
Place a round plate on top of the tart and carefully flip it over.
Slowly remove bottom of cake pan.
Let sit for a few more minutes; the sauce will thicken as it stands.
Add chopped nuts.
Cut and serve with a dollop of whipped cream.