Preheat broiler. Rinse mushrooms. Scoop out stems with a small spoon and save for another use.
In a small bowl, mix sausage with bread crumbs. Mound sausage mixture in mushrooms, then place, filled side up, in a rimmed 10- by 15-in. baking pan.
Broil 6 to 7 in. from heat until sausage is well browned, about 5 minutes. Lift mushrooms onto a platter, brush with oil, and top with parsley leaves.
Note: Nutritional analysis is per serving.