Submitted by: Louise M from Milwaukee, Wisconsin
Adjust an oven rack to the upper-middle position, about 5 inches from the upper heating element; heat the oven to 325 degrees.
Whisk the ketchup, powdered spices, Worcestershire, mustard, molasses, maple syrup, and vinegar together in a small bowl and set aside. Season the chicken with pepper. Place chicken in sauce and marinate 8 hours, or overnight, in the refrigerator.
Heat the oil in a heavy-bottomed, nonreactive, 12-inch ovenproof skillet over high heat, until beginning to smoke. Brown the chicken, turn and cook 1 to 2 minutes longer. Transfer the chicken to a plate and set aside.
Discard the fat in the skillet. off the heat, add the sauce mixture and use a wooden spoon to scrape up the browned bits on the bottom of the skillet. Simmer the sauce over medium heat, stirring frequently with a heatproof spatula, until the sauce is thick and glossy and a spatula leaves a clear trail in the sauce, about 3 to 4 minutes.
Off the heat, return the chicken to the skillet and turn to coat thickly with the sauce. Spoon extra sauce over each piece of chicken to create a thick coating.
Place the skillet in the oven and cook until the thickest parts of the chicken breasts register 130 degrees on an instant-read thermometer, 10-12 minutes. Set the oven to broil and continue to cook until the thickest parts of the chicken breasts register 155 degrees, 5-10 minutes longer.
Transfer the chicken to a platter and let rest 5 minutes. Meanwhile, whisk to combine the sauce in the skillet and transfer to a small bowl. Serve the chicken, passing the extra sauce separately.
Old World 3rd Street Spice is available in it's original form, with salt, on the website. It is called Old World Central Street Spice.