Combine onion, parsley, herbs, lemon peel and garlic; mix well. Combine agave and lemon juice; mix well. Place boneless lamb on flat surface, meat side up, and season with salt and pepper. Brush with agave mixture and sprinkle with herb mixture. Roll and tie. Rub roast with agave mixture. Bake on roasting rack in oiled roasting pan at 350°F, allowing 20-25 minutes per pound for medium-rare or to 145°F internal temperature; brush with agave mixture every 20 minutes. When all of agave mixture is used, brush with pan drippings. Let roast stand 5 to 10 minutes before carving. Add 1/2 cup water and deglaze pan, thicken if desired, and serve with lamb.