Prepare pasta according to package directions; drain. In a small saucepan, melt half of the butter and stir in flour to form a paste. Gradually add milk, stirring continuously to form a smooth sauce. Season to taste with salt and pepper. Remove from heat. Stir in Cheddar cheese until melted. In a large skillet melt remaining butter over medium-high heat. Sauté vegetables until just cooked. Add scallops; cook for 3 to 5 minutes until scallops are firm and lightly browned.
To serve: Spoon pasta onto plates, top with scallop mixture, cheese sauce and cracked pepper.
*Ideal with aged Cheddar. Use 2-year or 3-year Cheddar for added sharpness. Increase Cheddar for a richer sauce.