Preheat oven to 200C/180C fan-forced. Grease a 5cm-deep, 15cm x 26cm (6-cup capacity) ovenproof dish.
Heat milk and garlic in a small saucepan until mixture just comes to a simmer (do not boil). Remove from heat.
Arrange potato and apple slices, alternating, in rows in prepared dish. Push blue cheese in between slices. Strain milk mixture over potato mixture.
Cover with foil. Bake for 1 hour. Remove foil. Sprinkle with cheddar and walnuts. Bake for 30 minutes or until potato and apple are tender and cheese is melted and golden. Stand for 5 minutes. Serve.
Serving size: 10
Recipe courtesy of taste.com.au