Combine first 3 ingredients.
Melt 1 teaspoon of butter with oil in a large nonstick skillet over low heat.
While butter melts, sprinkle fish fillets with salt and black pepper. Place the flour in a shallow dish. Dredge fillets in flour; shake off excess flour.
Increase heat to medium-high; heat 2 minutes or until butter turns golden brown. Add fillets to pan; sauté 3 minutes on each side or until fish flakes easily when tested with a fork. Remove fillets from pan. Add broth mixture to pan, scraping to loosen browned bits. Bring to a boil; cook until reduced to 1/2 cup (about 3 minutes). Remove from heat. Stir in two teaspoons of butter with a whisk. Serve sauce over fillets. Garnish with lemon wedges, if desired.