In a bowl, mix the mustard, paprika, coriander, garlic powder, and salt.
Sprinkle the rub all over the ribs and pat it into the meat.
Tear foil into rectangles and wrap each rack in the foil to create sealed parcels of meat. Spread the wrapped racks onto a baking tray and place into the oven for 2 ½ hours.
Take the tray out of the oven and let them cool a little until they are cold enough to touch with your fingers. Tear back the foil and brush each rack with barbeque sauce. Put it back into the oven to bake for another 5-10 minutes until the sauce becomes sticky on the ribs.