Cook pasta according to package directions. Meanwhile, set aside 2 tablespoons of the butter for toping. Melt remaining 6 tablespoons butter in a large saucepan. Add bell pepper and garlic; cook 5 minutes, stirring occasionally. Sprinkle vegetables with flour, cook and stir 1 minute. Add milk and salt, bring to a simmer. Simmer uncovered 2 minutes, stirring frequently. Remove from heat; stir in 2 cups of the cheese until melted. Drain pasta, return to pot. Add cheese sauce and sausage, mix well. Transfer to buttered 13x9-inch baking dish, top with remaining 1-cup cheese. Melt reserved 2 tablespoons butter, toss with breadcrumbs. Spoon breadcrumbs over pasta and sprinkle with paprika, if desired. Bake in a 350°F oven 30 to 35 minutes or until sauce is bubbly and breadcrumbs are golden brown. Yield: 8 servings. (Recipe may be easily doubled using two baking dishes).