Add 1 tbsp butter and 1/2 tbsp olive oil to a pan over medium heat, then add in the onions. Fry for 15mins, stirring somewhat frequently, until the onions turn soft and golden.
Add in 1/8 tsp salt & black pepper, then lower the heat slightly to low-medium and continue frying for another 10-15mins, or until completely soft, deep golden and sticky/sweet. If any fond (flavour/char) builds up in the pan at any point, just add a dash of water and use your wooden spoon to scrape it off. Remove onions from pan when done.
Meanwhile, generously season both sides of the pork chops with salt and pepper and score the fat if it's relatively thick. Turn heat to high and add 1/2 tbsp olive oil. Place in the pork chops and fry for a couple of minutes on each side until golden brown (should only just be cooked through the centre). Stack the chops on top of each other with the fat aligning, then use your tongs to flip them on the sides and sear the fat for a couple of mins. Remove from pan and place to one side. Lower heat to medium.
You should be left with around 1 tbsp oil/fat left in the pan. Top up with butter or oil to make around that if needed (just eyeball it). Add the onions back to the pan and stir in 1 tbsp flour. Pour in 1 cup beef stock, stirring as you go to ensure no lumps form. Stir in 1/2 tsp Worcestershire, any resting juices from the pork and seasoning to taste, then add the chops back in. Spoon over some of the onions, top with cheese then place under the grill and broil until the cheese has melted (add a lid on top to melt the cheese if your pan isn't oven safe).
Garnish with fresh thyme then serve up and enjoy!