Prepare the red sauce as follows: In a heavy lO to 12 inch skillet, heat the vegetable oil over moderate heat

Add the onions and garlic while stirring frequently and cook for about 5 minutes, or until they are soft and translucent but not brown

Coarsely chop the chilies

Stir in the tomatoes and their liquid, the tomato puree, chilies, mustard, sugar, vinegar and salt, and bring to a boil over high heat

Cook briskly, uncovered, until the sauce is thick enough to hold its shape almost solidly in the spoon

Remove the pan from the heat and taste the red sauce for seasoning

Set it aside. For barbecuing the ribs, light a 2-inch-thick layer of charcoal briquettes in a charcoal grill equipped with a rotating spit

Let the coals burn until you have a low temperature, direct heat fire as described at the begin- ning of this chapter. Thread the spareribs on the spit, running the spit through the meat over and under alternate pairs of ribs

Then secure them at both ends with the sliding prongs

Fit the spit into place about 6 inches above the surface of the coals and barbecue the ribs for 45 minutes, or until they are lightly and evenly browned

Watch care- fully for any sign of burning and regulate the height of the spit accordingly. With a pastry brush, spread the red sauce evenly on both sides of the spareribs

Basting the ribs every 5 minutes or so, continue to barbecue them for about 30 minutes longer, or until they are richly colored and glazed with sauce. To serve, remove the spit from the grill, unscrew the prongs and slide the spareribs off the spit onto a heated platter

Before serving, insert skewers into each section of ribs if you like.