Preheat your oven to 400°F (205°C). Line a baking sheet with parchment paper.

If your puff pastry is still a bit rigid, let it sit on the counter for 10 minutes so it’s easy to work with.

Unfold the thawed puff pastry on a lightly floured surface. Trim any ragged edges and cut into 12 equal squares (about 3-inch squares). Keep them even so baking is uniform.

Cut the brie into 12 small cubes (about 3/4 inch). If you want less goo, remove some or all of the rind.

Spoon about 1 teaspoon of cranberry sauce into a small bowl and stir in the chopped nuts and rosemary if using.

Place a brie cube in the center of each square. Top with about 1 teaspoon of the cranberry mixture.

Fold corners over to create little parcels, or leave open-faced for a rustic look. If sealing, press edges gently and crimp with a fork.

Whisk the egg with 1 tablespoon water and brush each bite lightly.

Sprinkle a tiny pinch of flaky sea salt or more nuts on top if desired.

Bake for 12–15 minutes, until pastry is puffed and golden and brie is melty.

Let the bites cool 3–4 minutes, then arrange on a platter.

Garnish with a tiny rosemary sprig or drizzle of honey for sweet contrast and serve warm.