Make the marinade:
Crush the garlic cloves, sprinkle with a little salt, and mince finely into a paste; you should have 1-1/2 to 2 Tbs. Set aside. In a small bowl, combine the mustard, brown sugar, vinegar, olive oil, lemon juice, lemon zest, and chopped rosemary and whisk until thoroughly combined.
Marinate the chicken:
Wash and dry the chicken pieces thoroughly. Press down on the chicken breasts with the palm of your hand to flatten slightly (allowing rib cartilage to pop away or break in half). With a sharp knife, poke three or four slits in both sides of each piece of chicken to help the marinade penetrate. Put the chicken in a large nonreactive bowl. Add the garlic paste to the bowl and toss to coat the chicken. Scrape the marinade into the bowl of chicken and toss to coat (use your hands to distribute evenly). Add the rosemary sprigs and lemon slices, and toss to combine. Wrap the bowl well with plastic and refrigerate for at least 6 hours and up to 24 hours.
Roast the chicken
Take the chicken out of the refrigerator and pour the chicken and marinade (scraping the bowl) into one 10x15-inch or two 7x11-inch Pyrex baking dishes. Adjust the chicken so it’s skin side up and the pieces are evenly spaced. Tuck the marinated rosemary sprigs and lemon slices under and around the chicken pieces. Sprinkle each piece of chicken with a pinch of salt. Let the chicken sit for at least 20 minutes or up to an hour to warm up a bit so it will cook more evenly. Meanwhile, heat the oven to 400°F.
Put the chicken in the oven to roast. As it cooks, the marinade will bubble and begin to reduce. After 30 minutes, baste occasionally with the pan juices to help brown the skin and keep the chicken moist. The chicken is done when it turns deep brown and the pan juices have reduced (the sides of the pan will be very dark brown and look almost burned, and a paring knife will slide easily into a thigh), about 1 hour. The pan juices may separate, meaning the fat will be floating on top of the juices, which will be very thick.
Make the pan sauce.
Tip:Make the pan sauce while the pan is still hot; if you get delayed, use hot water to make the sauce, or put the pan back in the oven briefly to warm it.
Transfer the chicken pieces to a cutting board and tent with foil. Discard the rosemary sprigs but transfer the lemon slices to a small bowl and reserve.
Hold one end of the pan with a potholder and gently tilt the pan to let the juices run into one corner. With a large, shallow spoon, spoon off as much fat as possible but leave any savory juices and pan drippings behind (they may look clumpy). Add 2 Tbs. water to the pan (or 1 Tbs. to each of the two pans) and use a wooden spoon to scrape off enough of the baked-on pan drippings from the sides and bottom of the pan to form a slightly thickened, deeply colored, rich-looking sauce (you won’t need to scrape the whole pan). Taste the sauce— if it’s too intense, add a little more water; if it isn’t flavorful enough, keep scraping and stirring.
Cut each chicken breast in half by centering a large chef’s knife over it and then pushing down and slicing at the same time (the knife will cut right through the cartilage). Serve a thigh and half of a breast per portion, with a few spoonfuls of sauce. Garnish each serving with some of the roasted lemon slices and a fresh sprig of rosemary, if you like.
Serve with creamy polenta, a hash of red potatoes, or a simple risotto with Parmesan.
A bright, zippy red wine, like a young, fruity Barbera or a Côtes du Rhône, goes best with these assertive flavors.
nutrition information (per serving):
Photo: Scott Phillips