This lemon and dill vinaigrette is a natural complement to green beans. It's also great tossed with steamed asparagus or drizzled over sliced fresh tomatoes. To make this recipe serve 10, multiply all the ingredients by 2 1/2: use 2 1/2 pounds green beans, 3 tablespoons dill, 2 1/2 tablespoons each shallot, oil and lemon juice, 2 1/2 teaspoons mustard and 3/4 teaspoon each salt and pepper.