1/4 teaspoon vegetable or olive oil
1 thick slice onion
1 (5 ounce) boneless pork chop
1 teaspoon prepared mustard
Salt and pepper to taste
Sprig of rosemary or 1/4 teaspoon dried rosemary (optional)

Preheat oven to 350 degrees F. Oil well a 12-inch square of aluminum foil.

Place onion slice on half of foil.

Trim fat from chop, spread both sides with mustard, place on onion, sprinkle with salt and pepper, and top with rosemary if desired. Close foil to form a triangle, rolling edges and crimping firmly to seal, turning sealed edges upward. Ensure that packet is tightly closed, as a lot of juice is made during baking. Place in baking pan and bake 20 to 30 minutes, depending on thickness of chop, or until chop is no longer pink in center.

Transfer packet to dinner plate, open and turn chop with onion and juices onto plate. Serve, if desired, with baked potato or baked sweet potato.