In a medium bowl, beat 1 stick softened butter with a wooden spoon or spatula until creamy. Beat in pesto, blending well. Transfer butter to wax paper, and shape into a 6-inch log. Wrap, twisting ends of paper to seal, and refrigerate until firm.
Substitute 1 tablespoon prepared curry paste or sauce for pesto.
Substitute 1 tablespoon Caesar-salad-dressing mix for pesto.
Substitute 2 teaspoons hickory-barbecue seasoning mix for pesto.