How to Make It
Remove core from apples, and make 6 cuts around the top of each apple, three-fourths the way down, being careful not to cut through bottom of apple. (It should look like 6 apple wedges connected at bottom of apple.) Place each apple on a double layer of aluminum foil coated with cooking spray. Sprinkle each apple with 2 tablespoons of the brown sugar; top with 1 tablespoon of the butter. Sprinkle evenly with nutmeg and 1/4 teaspoon of the cinnamon. Wrap apples in foil, and fold foil to seal.
Preheat grill to medium-high (400°F to 450°F). Place apples on grates; grill, covered, until tender, 30 to 35 minutes. Remove apples from grill, and set aside.
Brush both sides of graham crackers with remaining 2 tablespoons butter; sprinkle evenly with remaining 1 tablespoon brown sugar and 1/4 teaspoon cinnamon. Lightly coat grill rack with cooking spray. Place graham crackers on grate, and grill, uncovered, until lightly charred, about 2 minutes per side.
Unwrap apples, reserving cooking liquid. Place apples in a shallow bowl. Drizzle wedges with reserved cooking liquid; top with ice cream. Break graham crackers into bite-size pieces, and sprinkle on top.