Mock Béarnaise Sauce
1/2 cup mayonnaise
1 tablespoon minced shallots
2 teaspoons chopped fresh tarragon or 1/2 teaspoon dried tarragon, crushed
1 1/2 teaspoons tarragon vinegar
1/8 teaspoon freshly ground pepper
Combine ingredients . Cover and let stand at room temperature to blend the flavors, at least 1 hour.