Prepare the Cranberry Sauce:

1. Cook the Cranberries: In a small saucepan, combine the cranberries, sugar, orange juice, cinnamon (if using), and salt. Bring to a simmer over medium heat, stirring occasionally.
2. Simmer: Let the mixture simmer for about 10 minutes, or until the cranberries have burst and the sauce has thickened slightly. Remove from heat and set aside to cool.

Assemble the Bites:

3. Preheat the Oven: Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper for easy cleanup.
4. Prepare the Puff Pastry: Roll out the puff pastry sheet on a lightly floured surface. Using a round cookie cutter or the rim of a glass, cut out small circles of pastry (about 3 inches in diameter).
5. Fill the Pastry: Place a small cube of Brie cheese in the center of each pastry circle. Top the cheese with a teaspoon of cranberry sauce.
6. Add Herbs (Optional): Sprinkle a few fresh thyme leaves on top of the cranberry sauce for added flavor.
7. Egg Wash: Lightly beat the egg and brush the edges of the pastry circles with the egg wash to ensure a golden finish when baked.
8. Bake: Arrange the filled pastry circles on the prepared baking sheet. Bake for 15-20 minutes, or until the puff pastry is golden and crispy and the Brie has melted.
9. Cool and Serve: Remove from the oven and allow the bites to cool for a few minutes before serving.