Preheat your oven to 400°F (200°C) and lightly grease a 24-count mini muffin pan with cooking spray or butter.
Unfold your thawed puff pastry on a lightly floured surface. Cut it into 24 equal squares (about 1½-2 inches each, depending on the size of your puff pastry).
Press each pastry square into the mini muffin pan to form a little cup. Add a cube of Brie to each one, then spoon about 1 teaspoon of cranberry sauce on top. Sprinkle with chopped toasted pecans and a pinch of rosemary.
Bake for 12–15 minutes, or until the puff pastry is golden and flaky and the cheese is melted.
Let them cool for 5 minutes before removing from the pan. Garnish with a tiny sprig of rosemary and a drizzle of honey, if you want to get fancy, and serve warm or room temperature.