Remove the membrane on the back of the ribs. Cut the rib rack in half (or more) if needed to fit in the water bath.
Coat the ribs with the mustard then the bbq rub.
Place in a vacuum seal bag and add the liquid smoke.
Seal and cook for 36 hours.
Remove and place on a foil lined baking sheet (can also grill).
Baste with bbq sauce and place under the broiler (or on the grill) for 5-10 minutes to caramelize.
Remove and slice ribs. Serve with extra bbq sauce if desired.
Notes
Cut the rack of ribs in half or thirds to ensure it fits in the sous vide container. vacuum seal each separately (you can even try different rubs and seasonings to see what you like the most!).
Line your baking sheet with foil or parchment paper to make cleanup easier.
You can also bake/grill the ribs with additional dry rub instead of bbq sauce if you prefer.