In a medium saucepan, combine the cranberries, water, brown sugar, and the leaves from 2 sprigs of thyme. Bring ingredients to a boil, boil for 2 minutes on medium heat or until cranberries have started to break down. Place in the refrigerator to cool.

In a saute pan, cook pancetta over medium heat until browned. Remove from saucepan and place on a paper towel. Set aside.

Preheat oven to 375°F. Fit your puff pastry sheet into an ungreased 14”x5" tart pan; you may need to cut pieces to fit. Prick the puff pastry all over with a fork, and then brush with egg white. Bake for 8 minutes or until shiny and just starting to puff up. Remove from the oven.

Spread prepared cranberry sauce evenly over the puff pastry. Top with sliced brie and pancetta bits. Return to the oven for 15 minutes or until the puff pastry is golden brown. Sprinkle with remaining thyme leaves. Serve warm.