Heat olive oil and butter in large saute pan on medium-high heat. Dust fish with flour and shake off excess. Add fish to pre-heated pan and lightly brown fish until fish flakes. Remove fish to serving platter. Add mushrooms and saute for 2 to 3 minutes. Add lemon juice and salt and pepper. Cook 30 more seconds.
Pour over fish and sprinkle with parsley.
Serve with buttered bowtie pasta and zucchini
-or- mashed potatoes, steamed frozen peas and peach pie.
A splash of white wine or sherry may be added before the lemon.