Grilled Burgers with Meyer Lemon Butter

Ingredients

• 1 bunch arugula 
• 6 tablespoons butter room temperature ()
• 1 tablespoon basil fresh finely chopped
• 1 tablespoon tarragon fresh finely chopped
• 1.5 pounds ground beef 15% ( fat)
• 1 teaspoon meyer lemon juice fresh
• 1 teaspoon lemon zest finely grated
• 1 tablespoon parsley fresh italian finely chopped
• 4  hotdog buns 
• 1 large tomatoes thinly sliced
• 4 servings vegetable oil (for brushing)

Equipment

• bowl
• baking sheet
• plastic wrap
• grill

Directions

1. Mix butter, all herbs, lemon peel, andlemon juice in small bowl. Season with saltand pepper. Measure 1/3 cup herb butter;transfer to sheet of plastic wrap (reserveremaining butter in bowl for spreadingon buns). Using plastic wrap as aid, formbutter into 3-inch-long log; wrap plasticaround to seal. Freeze until firm, about30 minutes.
2. Cut crosswise into 4 rounds.Flatten rounds into 2-inch-diameter disks.
3. Divide meat into 4 equal pieces. Usingdamp hands, form each piece into ball.Using thumb, make deep wide indentationin center of each ball. Press 1 lemon-butterround flatly into indentation, then pressmeat securely over butter to enclose.Flatten each burger into 31/2-inch-diameterpatty, leaving butter rounds horizontally incenter of each burger. DO AHEAD: Herb butterand burgers can be made 6 hours ahead.
4. Place burgers on baking sheet, cover withplastic wrap, and chill. Cover and chill herbbutter in bowl; bring to room temperaturebefore continuing.
5. Brush barbecue rack with oil. Preparebarbecue (high heat).
6. Sprinkle both sidesof burgers with salt and pepper.
7. Spreadremaining butter over cut sides of buns.Grill burgers until cooked through, 4 to 6minutes per side. Grill buns until slightlycharred, about 1 minute per side.
8. Place burgers on bun bottoms. Top withtomato slices and arugula leaves. Coverwith bun tops and serve.