This is very retro, but a little of it is good on fresh string beans that are just slightly cooked.

2 cups mayonnaise
4 anchovy fillets, minced
1 green onion, chopped
2 teaspoons chopped fresh parsley
2 teaspoons chopped fresh chives
1 tablespoon tarragon vinegar
1 teaspoon chopped fresh tarragon

Mix together mayonnaise, anchovy, green onion, parsley, chives, vinegar and tarragon.