In a large non-stick skillet, melt the butter over medium heat. Add the sliced onions and minced garlic to the pan and saute for 15 minutes to caramelize. Stir the onions periodically to avoid burning to the bottom of the pan.
While the onions are cooking, set your pork chops onto a plate in a single layer. Coat one side of the pork chops with the garlic powder, salt and pepper. Set aside.
Once onions have caramelized, move from the pan to a small bowl and set aside. Turn the heat to medium-high and sear each side of the pork chops (approximately 2 minutes per side). Once each side of the pork chops have been seared, move them back to the plate and turn the heat down to a medium-low temperature.
Add in the flour to the skillet and stir. Pour in approximately one tablespoon of the beef broth to the pan (this should form a paste with the flour). Slowly add in the rest of the broth and stir. Add the onions back in and then return to a medium heat. Let the broth come to a simmer, stirring constantly to thicken the sauce. Once the sauce has thickened, add the pork chops back into the pan and top with the mozzarella cheese. Cover and cook for another 4-5 minutes (3-4 minutes if you prefer a slightly pink centre).
Remove from heat and serve immediately with french bread and butter. Or serve over rice, with potatoes or atop some spiralled zucchini noodles. Garnish with some fresh parsley. Store in an airtight container in the fridge for up to 4 days.