.For the rub: Combine the ingredients and rub mixture evenly over the ribs.

For the sauce: Heat oil in the pressure cooker pot over medium heat until shimmering. Add the onion and cook until softened, about 5 minutes. Stir in garlic and cook until fragrant, about 30 seconds. Stir in ketchup, water, molasses, vinegar and mustard. Stir to combine. Cook for one minute (my additional step). Measure out and reserve one cup of the sauce.

Arrange the ribs upright in the pot, with meaty sides facing outward, then pour reserved sauce over the ribs. Lock the pressure cooker lid in place and bring to high pressure over medium-high heat. As soon as the pot reaches high pressure, reduce heat to medium and cook for 15 minutes adjusting heat as needed to maintain pressure. Then let it do a natural pressure release for 15 minutes.

Before serving: Preheat the broiler with the rack 6 below the flame. Remove ribs (meaty side up), with tongs, onto a foil-lined baking sheet with a baking rack set on top.

Skim off the excess fat from the sauce, in the pot. Simmer the sauce until it is thickened, about 10 minutes, to equal about 2 cups. Brush the ribs with some of the sauce, flipping them over and brushing both sides.

Starting with the meaty side up, broil until browned and sticky, for 2-3 minutes per side. Watch closely, as the sauce has sugar and can burn! Turn over a few times, adding additional sauce- for a total of 10-15 minutes.