See Dr. Roberts demonstrate this as part of a complete Thanksgiving-inspired meal at this cooking demo on YouTube: https://www.youtube.com/watch?v=uYYAyYtA8Rk
Makes 10–11 mushrooms, recipe doubles easily
8 oz mushrooms (about 11), let them sit on the counter overnight to open up
1 thick slice iDiet legal bread or 1 slice Fiber One Bread
3 T warm milk
1/4 C chopped parsley
1 medium clove garlic
1/3 tsp salt
1/4 tsp pepper
Pinch of basil and nutmeg
1 tsp butter
1/2 oz parmesan cheese
If you have a food processor, make the bread into crumbs; if not soak the bread in the warm milk and then break up well with a fork. Sauté the onion and garlic in butter for 5 minutes until cooked and lightly browned. Add parsley and cook briefly. Mix with the bread/milk mix, egg, and seasoning (except cheese).
Spray bottoms of mushrooms lightly with Pam, turn over and pile in the filling. Bake covered 30-40 minutes at 350°F until the mushrooms are almost cooked, then add cheese, uncover and cook another 5 minutes to lightly brown. Serve immediately.