Preheat a convection oven to 375°F (190°C) and apply non-stick coating to a 24-count mini muffin tin.
Unroll the crescent dough sheet onto a lightly floured surface and use a rolling pin to flatten any perforations.
Using a pizza cutter, divide the dough into 24 equal squares (approximately 2 inches by 2 inches).
Transfer each dough square into a mini muffin slot, pressing firmly against the bottom and sides to create a cup.
Place one 3/4-inch cube of Brie cheese into the center of each dough cup.
Top each cube of Brie with 1 level teaspoon of whole berry cranberry sauce.
Distribute the chopped pecans evenly over the cranberry sauce layer.
Bake for 10 to 12 minutes until the pastry corners are golden brown and the cheese is bubbling.
Remove from the oven and immediately garnish each bite with a small sprig of fresh rosemary.
Allow the bites to rest in the pan for 5 minutes to set before extracting with a small offset spatula.