Mix the chopped rosemary, garlic, lemon zest, lemon juice, one tablespoon olive oil, two teaspoons salt and half teaspoon pepper together in a small bowl to make a paste.

Place chickens on a sheet pan with the skin side up - and loosen the skin from the meat with your fingers. Place half of the paste under the skin of each chicken.

Rub any remaining paste on the outside and underside of the chickens.

Turn chicken skin side down and scatter the lemon slices and sprigs of rosemary over each chicken. Season with salt and pepper. Roll each chicken up, cover with plastic wrap and refrigerate for at least 60 minutes.

Heat a grill with coals. Spread the coals out in a dense layer and brush the grill with oil.

Unroll the chickens, place them on the grill and cook for a dozen minutes on each side.