Season pork chops on one side with salt, pepper and garlic powder; set aside.
In the same skillet over medium-high heat, add butter and oil. When sizzling, add chops, seasoned side down, and cook for 3 to 4 minutes or until brown; season the top with salt, pepper and garlic powder.
Flip the meat and cook for 2:30 to 3 minutes. Transfer to a plate.
Reduce heat to medium and return onions including any accumulated juices. Add flour, a little at a time, and stir well before adding more; cook for 2 minutes.
Pour in broth and mix until the sauce thickens and the texture turns creamy. Stir in Herbes de Provence. Return pork chops to skillet, including any accumulated juices, and spread a thin layer of Dijon mustard on top of each. Evenly sprinkle cheese, enough to cover the chops.
Cover and cook until cheese is melted and the internal temperature of the pork reaches 145ºF.
Serve pork chops over mashed potatoes, spoon sauce and caramelized onions on top.