Whisk together milk and egg.
Sprinkle fillets with salt and 1/8 teaspoon pepper. Dredge fish in flour; dip in milk mixture, and dredge in breadcrumbs.
Melt 1 tablespoon butter in a large skillet over medium heat; add fish, and cook 2 to 3 minutes on each side or until fish flakes with a fork. Remove fillets, and drain on paper towels; keep warm.
Wipe skillet clean, and melt remaining 2 tablespoons butter over medium-low heat. Add remaining 1/8 teaspoon pepper, cream cheese, and remaining ingredients, stirring until smooth. Pour sauce over fillets.
* Baby Swiss cheese may be substituted for fontina cheese.