Peel onions and roll in flour.
Place in 1-quart casserole.
Stir in butter, salt, and milk.
Cover with plastic wrap.
Microwave at HIGH 5 minutes.
Add 1/4 cup peanuts, pimiento, and mushrooms.
Microwave at HIGH 4 to 5 minutes.
Top with remaining peanuts, bread crumbs, and parsley.
Microwave, uncovered, at HIGH 4 to 5 minutes.
Let stand, covered, 3 minutes before serving.