Place sweet potatoes in a large saucepan. Cover with water; add ½ teaspoon salt. Bring to a boil; reduce heat. Cover and gently boil for 12 to 15 minutes or until fork-tender. Drain well.

Return potatoes to saucepan. Add ¼ cup butter; mash with a potato masher until smooth. Stir in enough milk until light and fluffy; season to taste with salt and ¼ teaspoon black pepper. Heat canola oil in a large cast iron skillet. Add pork chops and cook over medium heat for 7 to 9 minutes or until pork reach 145°, turning halfway thorough. Transfer pork chops to a plate; cover to keep warm.

Whisk together apple juice, corn starch, apple pie spice and mustard; set aside.

Melt remaining 2 tablespoons butter in same skillet over medium heat. Add apples, onion and ½ teaspoon thyme. Cook for 6 to 8 minutes or just until softened, stirring frequently. Push apples and onion to side of skillet. Add apple juice mixture to center of skillet; cook and whisk for 1 to 2 minutes or until slightly thickened. Return pork chops to skillet and heat through. Garnish with additional thyme, if desired. Serve with mashed sweet potatoes.