Grilled Burgers with Meyer Lemon Butter

Name: Grilled Burgers with Meyer Lemon Butter
Ingredients: 6 tablespoons (3/4 stick) butter, room temperature; 1 tablespoon finely chopped fresh tarragon; 1 tablespoon finely chopped fresh basil; 1 tablespoon finely chopped fresh Italian parsley; 1 teaspoon finely grated Meyer lemon peel or regular lemon peel; 1 teaspoon fresh Meyer lemon juice or regular lemon juice; 1 1/2 pounds ground beef (15% fat); Vegetable oil (for brushing); 4 sesame seed hamburger buns; 1 large tomato, thinly sliced crosswise; 1 bunch arugula; Ingredient info: Meyer lemons are a bit sweeter than regular lemons and have a slight floral note. They're available at some supermarkets and farmers' markets.