Season the ribs with the salt, concentrating most of the salt to the meaty side (and not the bony side).
Slice in between the bones to cut the racks into individual ribs.
Place the ribs on a rimmed half sheet pan, and pour 2/3 of the barbecue sauce on top (which should be about 1 cup of sauce). Toss the ribs well, until evenly coated with the sauce. Then place them all meaty side up.
Cover the ribs very tightly with foil, and cook for 1 hour and 45 minutes.
Remove the foil and baste the ribs with half of the remaining barbecue sauce, about 1/3 cup. Increase the oven temp to 350F and bake uncovered for another 30 minutes.
Baste the ribs with the remaining barbecue sauce and bake for another 20-30** minutes, until the barbecue sauce is caramelized. They should no longer be saucy and wet, but sort of sticky and glazed. Enjoy!
*The St. Louis Style Spare Ribs I purchase from the butcher are ready to go, without the membrane. If yours have a membrane, simply pull it off with your fingers, and discard.**Barbecue sauces with higher concentrations of sugar will burn faster, so keep your eye on them.