Bend back outer green petals until they sanp off easily near the base. Continue to snap off and discard petals until central core of pale green petals is reached. Trim outer dark green layer from base. Using stainless steel knife to minimize discoloration, cut of top 1/3 of petals; discard. Cut stem level with base. Halve each artichoke and slice each half into fourths, removing the hairy choke with a small knife. Place in mixture of lemon juice and water while working on remaining artichokes to retard discoloration. Melt 2 tb butter in large skillet; saute artichokes, add 2 tb water,, cover and simmer for 5 to 10 minutes or until tender. Melt remaining butter in large, heavy saucepan; saute prosciutto, shallots, pepper and garlic for 5 minutes or until pepper is tender. Add wine and boil for about 3 minutes or until reduced by half. Mix in cream and pesto. Cook for about 5 minutes or until sauce thickens. Salt and pepper to taste. Keep sauce warm. Place pasta in large serving bowl and top with cooked artichokes. Pour sauce over top. Add Parmesan and toasted pine nuts. Toss to mix well. Serve immediately.