Cut the pork shoulder in half and trim all excess fat - there will be quite a bit. It's fine if you cut the pork up to get at the fat
Mix the salt and pepper with the Schwartz Perfect Shake Classic BBQ Seasoning and rub it all over the pork. Make sure to massage. Place the pork in the fridge for a few hours or use immediately
Place the Instant Pot into Sauté mode and spray with low calorie cooking spray. Brown the pork on all sides, don't worry if the bottom of the pot browns
Remove the pork from the pot and deglaze with a bit of the stock. Make sure all browned bit are off the bottom
Tip in the onions and cook until they soften. Add the pork back to the pot and pour in the stock and Worcestershire sauce
Place the pork and onions on a plate and run the remaining juices through a fat separator to get rid of the fat. Return the juices to the pot, and put the pot into Sauté mode
Add the pork into the sauce and stir well. Place the pot into 'Keep Warm' if you want to go back for seconds. You probably will!!
Spray a frying pan with low calorie cooking spray and cook the onions and garlic until the onions are soft
Add the tomato puree and tinned tomatoes and cook for 5 minutes on high, stirring frequently
Add in the rest of the ingredients, lower the heat and simmer for 20 minutes, the sauce should thicken nicely
Place into a sterilised jar, and store in the fridge until ready to use. Use within a week.