Mash the garlic with the salt, then combine it in a bowl with the honey, soy sauce, chicken broth, and ketchup or tomato puree. Pour mixture over the ribs, refrigerate, and let them marinate for several hours or overnight. Turn several times to coat all surfaces.
Preheat oven to 450 F.
Place the spareribs in a foil-lined roasting pan with their marinade. Bake for 10 minutes at 450 F, then reduce oven temperature to 325 F. Continue baking for 1 hour and 20 minutes, or until the ribs are beautifully tender. Baste occasionally to enhance the flavors and keep them moist.
Put the ribs on a serving platter and keep them warm while you thicken the sauce. Add enough water to the liquid in the roasting pan to make 1 cup. Make a paste with the cornstarch and a small amount of water, then blend into the liquid, cooking until thickened and clear. Serve with the spareribs.