Preheat oven to 375 degrees. Coat a mini muffin pan with nonstick cooking spray.
Roll out the crescent dough and pinch the seams together with your fingers so that it forms one large rectangle. Using a sharp knife or pizza wheel, cut the dough into 24 squares.
Cut brie into 24 small cubes.
Press dough squares into each compartment of the muffin tin. Place one cube of brie into each piece of dough. Top brie with 1 tsp. of cranberry sauce and some pecans. Bake 13-15 minutes or until dough is puffed and golden.
Allow to cool 10 minutes, then remove tartlets from muffin tin and sprinkle with chopped rosemary.