- Preheat oven to 375°F. Mist an 8 x 10-inch baking dish with cooking spray.
- In a medium saucepan on medium, heat oil; add leeks and garlic and cook, stirring occasionally, until softened, about 5 minutes. Stir in milk, thyme, nutmeg, salt and pepper, and bring to a boil (still on medium). Remove from heat.
- Reserving most of milk mixture, line base of dish with leeks using a slotted spoon. Arrange alternating slices of celery root, potatoes and pears, starting with edges of dish then filling center with slices to fit.
- Pour milk mixture evenly over top. Loosely cover with foil and bake for 1 hour. Remove cover, sprinkle with cheese and continue baking until tender and golden brown, 20 to 30 minutes more. Let stand for 5 minutes before serving.
- Serving Size 1/6 of gratin
- Calories 268
- Carbohydrate Content 41 g
- Cholesterol Content 21 mg
- Fat Content 9 g
- Fiber Content 5 g
- Protein Content 9 g
- Saturated Fat Content 4 g
- Sodium Content 262 mg
- Sugar Content 16 g
- Monounsaturated Fat Content 0 g
- Polyunsaturated Fat Content 0 g