Preheat your oven to 375 degrees Fahrenheit. Lightly grease a mini-muffin tin.
If using crescent roll dough, separate the dough into individual triangles. Cut each triangle into quarters. If using puff pastry, roll it out and cut it into 2-inch squares.
Press the dough pieces gently into the cups of the mini-muffin tin, forming small cups.
Place one small cube of brie cheese into the bottom of each dough cup.
In a small bowl, mix the cranberry sauce with the orange zest and chopped rosemary, if using.
Spoon about 1/2 teaspoon of the cranberry mixture over the brie in each cup.
Brush the edges of the dough lightly with the beaten egg wash.
Bake for 12 to 15 minutes, or until the pastry is golden brown and the cheese is melted.
Let the bites cool in the tin for 5 minutes before carefully removing them to a wire rack to cool slightly before serving.
Notes
You can prepare these bites up to 24 hours ahead. Store unbaked bites covered in the refrigerator. Add 2-3 minutes to the baking time if baking directly from cold.
For make-ahead convenience, you can assemble the bites completely and freeze them on a baking sheet. Bake from frozen, adding about 5 minutes to the bake time.
If you do not have orange zest, use 1 teaspoon of orange juice mixed into the cranberry sauce instead.