Using a sharp knife or kitchen scissors, trim off the rind and most of the fat layer until you’re left with a 1cm layer of fat on the chops. Chop the trimmed fat into blocks and cut the rind into small blocks.
Heat a pan and gently render the fat until there is a good amount in the pan, then fry the chopped rind in that until crispy. Season with a generous pinch of sea salt. Remove the rind but reserve the fat.
Season the meat on both sides with sage, salt and black pepper. Fry the chops fat side first (hold upright with tongs) until the fat has good colour. Then do the same on the bone side, still holding the chops upright. Now fry the chops for 2 minutes on each side, turn over and fry for another 2 minutes. Keep a spatula handy to press the chops down in the pan to stop them from curling up as the meat browns. Continue to fry the chops, turning them over as needed for a total cooking time of about 10 minutes. Use your judgment and let the thickness of the chops determine the cooking time. Remove and allow the meat to rest while you make the sauce.
Add the onions and mushrooms with the lump of butter to the same pan until fragrant. Beat in the flour and cook for another minute. Beat in the stock and cook for a few minutes until the sauce is thick and glossy. Stir in the cream and put the chops back in the sauce; heat through and serve with mashed potatoes. Garnish with the crispy bits of skin.
Tip: Don’t make the stock too concentrated or your sauce will be too salty. You can always add salt later, but if the sauce is too concentrated from the start, you’ll battle to get the balance right.