In medium saucepan, melt 2 Tbsp butter; add onion and cook until tender. Add water; bring to a boil. Stir in noodles and butter & herb sauce; continue boiling over medium heat, stirring occasionally, 8 minutes or until noodles are tender. Meanwhile, in large skillet, heat remaining 2 Tbsp butter with olive oil; cook garlic over medium-high heat 30 seconds. Add shrimp and artichokes; cook, stirring occasionally, 3 minutes or until shrimp turns pink. Stir in parsley and pepper. To serve, combine shrimp mixture with hot noodles. Garnish, if desired, with watercress.