In a small saucepan, melt butter over medium low heat. Stir in flour. Blend in stock. Cook over medium heat until thickened and bubbly after 5-7 minutes. Add jelly. Stir until melted. Add wine and heat just to boiling. Serve sauce warm. Makes about 1 cup.
Remove all surface fat and silver-skin from tenderloin. Slice across grain into one-inch-thick fillets.
In medium skillet, melt butter in oil over medium-low heat. Add fillets; cook to desired doneness over medium high heat, turning once. Salt and pepper to taste.