Preheat oven to 425°.
Trim fat from pork. Place pork on a broiler pan coated with cooking spray. Combine mustard, 2 tablespoons syrup, rosemary, salt, and pepper in a small bowl; brush over pork. Insert meat thermometer into thickest part of pork. Bake at 425° for 25 minutes or until thermometer registers 160° (slightly pink).
While pork is baking, heat a nonstick skillet over medium-high heat until hot. Add apples, and saute 5 minutes or until lightly browned. Reduce heat to low, and add 4 tablespoons maple syrup. Simmer 10 minutes or until apples are tender, stirring occasionally. Cut pork crosswise into slices; spoon cooked apples over pork.