Make the jus
Preheat the oven to 325°F. Place the bones in a roasting pan and drizzle with the oil. Roast, stirring several times so they cook evenly, until the bones turn light golden-brown—30 to 40 minutes total. Leaving the oven on, transfer the bones to a paper towel-lined plate to drain and wipe the pan dry. Return the roasted bones to the pan; add the celery, onions, carrots, garlic, thyme, and peppercorns. Pour in the wine and stir in the tomato paste and salt. If appropriate, add water to cover. Return the pan to the oven and cook for 4 hours, adding water as necessary to keep the bones covered.
Pour the liquid from the pan through a mesh strainer into a small saucepan; discard the bones. Bring the liquid to boiling over medium heat and boil gently until it is reduced to 2-1/2 cups, skimming off any impurities. Transfer the jus to a storage container.
Make the stuffing
To clean the livers, use the tip of a sharp paring knife to remove the sinew that runs into the meat and trim off any yellow spots or unevenly colored areas. Rinse the livers under cold running water and pat them dry thoroughly with paper towels. Coarsely chop the livers into 1/2-inch pieces. Heat the oil in a large sauté pan over medium heat. Add the onions, celery, and garlic, cook for 2 minutes; lower the heat to medium-low and continue to cook until the vegetables are translucent and begin to soften—6 to 8 minutes. Add the livers, sage, salt, and pepper; sauté until the livers are cooked—about 5 minutes. Transfer the mixture to a paper towel-lined plate to drain. Place the crushed matzos in a medium bowl; add the liver mixture and mix well with a wooden spoon. Taste the stuffing and add more salt or pepper if you wish
Stuff and roast the hens
Trim any excess fat from the hens; wash them under cold water and pat dry with paper towels. Set aside.
Mix the carrots, celery, and onions in the bottom of a roasting pan large enough to hold all 4 hens.
Preheat the oven to 400°F. Loosely fill the cavity of each hen with stuffing. Drizzle 1-1/2 tsp. oil over each hen and rub into skin. Sprinkle each hen with salt and pepper. Truss the hens with twine (tie the legs together, tuck the wings under the backs). Place the hens, breast up, in the roasting pan, on the bed of chopped vegetables. Dot each with the butter, dividing equally. (If there is extra stuffing, place it in an appropriate size casserole or ramekin; add it to the oven with the hens about halfway through the roasting time.)
Place the pan in the oven and roast for 10 minutes, lower the heat to 325°F. Roast for 40 minutes more, until done (the internal temperature of the thigh should register 160° on an instant read thermometer), checking from time to time that the hens are browning evenly and rotating the pan 180 degrees about halfway through the cooking time.
Make the sauce and serve
Transfer the hens to a cutting board and cover with foil to keep warm. Transfer the vegetables and pan juices to a small saucepan and add 1 cup of the roasted chicken jus. Bring to simmering over medium heat; simmer for 10 minutes. Strain the sauce through a fine mesh strainer into another pan or serving pitcher; discard the solids and keep the sauce warm.
Slice the thighs, legs, and breast meat from each hen—as you would when carving a turkey. Carefully spoon the stuffing from inside each hen and place on individual plates. Arrange the meat from one hen on top of the stuffing on each plate. Spoon the sauce over the top and serve.
Make Ahead Tips
You can make the roasted chicken jus several days ahead; store, covered in the refrigerator.
Serve with braised cabbage.
You’ll have about 1-1/2 cups of roasted chicken jus leftover. It will keep in the freezer for up to 1 month.
Photo: Renee Comet