Rinse lamb shanks and pat dry with paper towel. Season all sides with Ras el Hanout, salt, pepper and cayenne pepper.
Switch pressure cooker to sauté mode. When the pot is hot, add 1 tbsp avocado oil and brown all sides of the shanks. Work in batches so as to not overcrowd the pot. Transfer browned meat to a tray and set aside.
Add pomegranate juice and use a wooden spoon to scrape any brown bits on the bottom of the pot.
Nestle lamb shanks in the bottom of the pot, cover with onions, celery, carrots, fennel and garlic. Pour in stock and bring liquid to a simmer.
Switch setting to manual, high pressure and set the cooking timer for 75min. Close the lid and set valve to the sealing position.
Once cooking timer has transpired, release pressure manually. Using a slotted spoon, carefully transfer lamb shanks and vegetables to a tray. Personally, I discard all vegetables except the carrots at this point. But you’re the boss, applesauce.
Switch setting to sauté and cook the sauce at a steady simmer until reduced by half (approx. 12-15min), stirring occasionally. *Tip: resist the urge to thicken the sauce with arrowroot starch. Instead allow the sauce to slowly cook down so as to naturally thicken and intensify the flavours.
Serve lamb shank and carrots over cauliflower purée. Spoon reduced sauce overtop and garnish with toasted almonds and reserved fennel fronds.