In a small bowl, mix the spice rub ingredients.
Rinse ribs and pat dry with paper towels. Remove the membrane on the back of the ribs.
Season the baby back ribs generously on both sides with the spice rub.
Place the trivet (or pressure cooker rack) in the bottom of your pressure cooker. Add the juice and the apple cider vinegar.
Place the ribs inside the pressure cooker, standing up and wrapping around the pot. Close the lid and pressure cook on high for 23 minutes (25 if the ribs are meaty).
Once done, allow the instant pot to naturally release for 5 minutes, then open the valve to release the remaining pressure.
While the ribs are cooking, prepare the BBQ sauce. Place all the ingredients (except the ribs cooking liquid) in a small saucepan and stir to combine. Simmer on low heat for about 15 to 20 minutes, stirring occasionally. When the ribs are done, remove 1/4 cup of the cooking liquid and add it to the sauce. Stir and simmer on low for an additional 5 minutes.
Remove the ribs from the pressure cooker and place them on an aluminum foil lined baking sheet. Brush them generously with the BBQ sauce (on both sides), and place them under the broiler for about 5 minutes or until slightly charred. Serve with the remaining BBQ sauce.