Preheat your oven to 190°C (375°F). Line your mini muffin tin with parchment paper or lightly spray it with non-stick spray to prevent sticking.
Unfold the thawed puff pastry and cut it into 24 small squares, about 2 inches each. Gently press each square into a muffin cup, shaping them into little cups with the edges slightly overlapping the sides.
Bake the pastry cups for 8 minutes until they just start to turn golden and are slightly puffed up. Remove from the oven and set aside.
While the pastry bakes, prepare the cranberry sauce: in a small saucepan, combine cranberries, sugar, and orange zest. Cook over medium heat for about 10 minutes, stirring occasionally, until the cranberries burst and the mixture thickens into a jam-like consistency.
Once the pastry cups are out of the oven, gently place a small slice of brie into each pastry shell. Top each with a teaspoon of the warm cranberry sauce, letting it pool around the cheese.
Return the filled pastry cups to the oven and bake for another 5-7 minutes, until the cheese is melted and bubbly, and the pastry is crisp and golden.
Remove from the oven and let rest for about 2 minutes. Carefully transfer the bites from the muffin tin to a serving platter using a small spoon or spatula.
Serve the cranberry brie bites warm, garnished with fresh herbs if desired, and enjoy their crispy, gooey, and tangy flavor combination.