Mix together the paprika, sugar, salt, and pepper and rub the ribs liberally with the mixture. Put each rack into a cooking pouch and vacuum seal Submerge the pouch(es) in the water oven and cook for 48 hours
for the glaze
In a saucepan, fry the onion and garlic in a little olive oil until soft.
Add the fennel and cumin seeds and fry for a minute or two more.
Add the remaining ingredients and cook over a low heat for half an hour.
Remove from the heat and blitz (blend) the sauce with a hand-held food processor for 30 seconds. (Alternatively let it cool a little and pour into a blender jar or food processor and blend.)
Remove any pulp left in the sauce by straining through a sieve.
Return the sauce to the heat and reduce it until it is reasonably sticky.
to finish
When you’re ready to eat, remove the ribs from their pouches, spoon over some of the glaze and seal in a frying pan or on the BBQ until the meat starts to blacken a little. Use the remaining glaze as a dipping sauce.