Combine the cranberries, sugar, orange juice, cinnamon, and a pinch of salt in a small saucepan. Cook over medium heat, stirring occasionally, until the cranberries burst and the mixture thickens into a jam-like consistency, about 10-12 minutes. Remove from heat and let it cool slightly.
Preheat your oven to 400°F (200°C). While the oven warms, roll out your thawed puff pastry sheet on a lightly floured surface. Cut the pastry into squares about 3x3 inches to fit into the muffin tin cups with some overhang.
Press each puff pastry square gently into the muffin tin cups, forming little cups with the edges sticking out slightly above the rim.
Place a small piece of Brie cheese into the bottom of each puff pastry cup. Spoon about a teaspoon of the cranberry filling over the cheese. If using, sprinkle cooked, crumbled turkey bacon on top.
Brush the exposed edges of the puff pastry with the beaten egg to achieve a golden, glossy finish. Bake in the preheated oven for 15-18 minutes or until the pastry is puffed and golden brown, and the cheese is melted.
Remove the baked Cranberry Brie Bites from the oven and let them cool in the tin for a few minutes before transferring to a cooling rack. Serve warm or at room temperature.
