Season the pork chops with salt, pepper, garlic powder and dried thyme on both sides. Set aside.
Heat a 10 inch skillet over medium heat (an oven safe or cast iron skillet if you are using the broiler to melt the cheese). Add the olive oil and butter. When the butter is melted, add the onions and cook stirring regularly for about 15 to 20 minutes or until the onions are golden brown and caramelized. If the skillet gets too hot, turn the heat to medium-low. You want the onions to cook slowly, not to get charred.
Remove the onions from the skillet and set aside. Drizzle a bit of olive oil into the skillet, if needed. Turn the heat to high and sear the pork chops for about 1 to 2 minutes per side or until golden brown. Remove onto a plate. At this point, the pork chops are not cooked through.
Turn the heat to medium and return the onions to the skillet. Stir in the garlic and 1 teaspoon of fresh thyme. Cook for a minute. Sprinkle in the flour and mix well. Cook for 2 minutes, stirring constantly.
Stir in the wine and mix well. Stir in the broth, Worcestershire sauce and Dijon mustard. Mix until well incorporated. Season to taste with salt and pepper.
When the sauce comes to a simmer, nestle the pork chops in the sauce. Cover and cook for about 5 minutes or until the pork internal temperature reaches 145 to 150 degrees Fahrenheit for medium rare. Top the pork chops with cheese, close the lid and wait a couple of minutes until the cheese melts OR follow my favorite method - BROIL. Turn the oven to broil and place the skillet about 4 inches from the heat source. Broil for a few minutes or until the cheese melts and gets gooey and a bit golden (keep an eye on it, it works fast!)
Garnish with fresh thyme sprigs and serve immediately.