Asparagus and Green Beans with Tarragon Lemon Dip

1 pound asparagus, trimmed

1 pound fresh green beans, trimmed

salt

1 cup mayonnaise

1 lemon, zested and juiced

1 small shallot, finely chopped

2 tablespoons chopped fresh tarragon, (4 sprigs), chopped, plus sprigs for garnish

2 tablespoons chopped parsley leaves, plus sprigs for garnish

Few grinds freshly ground black pepper

Cook asparagus spears and green beans in 1-inch of salted boiling water, covered, for 3 or 4 minutes. Drain and cool the vegetables and arrange them on a serving plate. Combine the dip ingredients in a small bowl and garnish with sprigs of parsley and tarragon and set dip along side vegetables on serving dish.