Lobster and Butter Lettuce Salad

INGREDIENTS

• 1 live lobster, about 1 lb.
• 2 Tbs. Champagne or white wine vinegar
• 1 1/2 tsp. Dijon mustard
• 1 1/2 Tbs. chopped fresh tarragon
• Salt and freshly ground pepper, to taste
• 6 Tbs. extra-virgin olive oil
• 2 heads butter lettuce, torn into large pieces
• 1 avocado, peeled, pitted and cut into slices
• 1/4 inch thick
• 1 ruby red grapefruit, peeled and segmented
• 1 Tbs. chopped fresh chives