Preheat oven to 400 degrees. Melt the butter and olive oil in a large cast iron or other oven safe skillet over medium-high heat. Add sliced onions and sure 3-5 minutes until soft. Add 4 TBSP beef stock and continue to cook, stirring occasionally for about 15 minutes.
As the onions are sautéing season both sides of the pork chop with salt, black pepper, thyme and garlic powder. Transfer onions to a plate.
Reduce heat to medium and add a drizzle of olive oil to the skillet and cook pork chops, about 3-4 minutes per side until golden brown. Transfer them to a plate
Return cooked onions to pan and sprinkle with flour. Stir to coat onions with flower and cook about 1 minute. Add remaining beef stock and stir often until boiling. Season with a pinch of salt and pepper
Transfer pork chops back into the pan, spooning some of the beef stock/onions over the tops of the pork chops. Bake 8-10 minutes.