CRESCENT DOUGH: roll pastry out into a 10 x 14-inch rectangle. Cut the sheet lengthwise into 6 even strips, then crosswise into 4 even strips. You should have 24 squares. Separate and press each square of pastry gently into each muffin cup.
PUFF PASTRY: Use 2 sheets of semi-thawed puff pastry. (Semi-thawed is easier to cut.) Cut each pastry sheet lengthwise into 3 even strips. Then crosswise into 4 even slices. You should have 12 pieces per puff pastry sheet (24 in total).
BRIE: Make sure to cut the Brie into 24 equal pieces (about 3/4-inch or 2cm pieces).