Preheat the oven to 375°F. Coat two mini muffin pans generously with baking spray so the baked cranberry Brie bites can be removed easily.
Unroll the 8 oz crescent dough onto a clean work surface. Press the perforated seams firmly together until the dough forms one continuous sheet.
Cut the sheet into 24 approximately equal squares, making six columns in one direction and four rows in the other.
Fit one square of dough into each prepared mini muffin cavity. Press the pastry gently against the bottom and sides to create a small cup.
Divide the 8 oz Brie into 24 pieces, removing the rind if preferred. Set one portion of cheese in the center of every crescent dough cup.
Stir the 1/2 cup cranberry sauce briefly if necessary to make it easier to portion. Spoon approximately 1 teaspoon of cranberry sauce over the Brie in each pastry cup.
Transfer the filled mini muffin pans to the preheated oven. Bake for 10–12 minutes, until the crescent pastry becomes puffed and lightly golden.
Remove the pans from the oven and allow the bites to rest for several minutes before taking them out of the tins. The melted Brie will be extremely hot immediately after baking.