In a 4-quart Dutch oven or large saucepan cook pasta according to package directions; drain. Return to pan; cover and keep warm.
Meanwhile, cut off and discard upper stalks from fennel bulbs. Cut bulbs lengthwise into quarters. Remove and discard core. Cut fennel into thin strips.
Cook garlic and crushed red pepper in olive or cooking oil and margarine in a large skillet over medium-high heat for 15 seconds. Add fennel to skillet; cook and stir for 5 minutes more. Add sweet pepper strips; cook 3 minutes more. Add beans and thyme; cook 2 minutes to heat through. Add fennel mixture to warm cooked pasta; toss gently. Season to taste with black pepper. Serve with Parmesan cheese. Makes 4 main-dish servings.