Potato-and-Celeriac Gratin

Ingredients

• 0.3 teaspoon pepper black
• 1.5 pounds celery root peeled (celery root)
• 3 tablespoons flour all-purpose
• 2  garlic cloves halved
• 4 ounces gruyère cheese divided grated
• 2 cups milk 1% low-fat
• 2 pounds potatoes red peeled cut into 1/4-inch-thick slices
• 0.5 teaspoon salt 
• 4  thyme sprigs divided

Equipment

• frying pan
• sauce pan
• oven
• whisk
• baking pan

Directions

1. Preheat oven to 35
2. Rub the sides and the bottom of an 11 x 7-inch baking dish coated with cooking spray with garlic halves. Crush garlic halves; set aside.
3. Cut celeriac into 1/4-inch-thick slices; cut slices into quarters to measure 2 cups, reserving remaining celeriac for another use.
4. Place 2 cups celeriac, potatoes, and 3 thyme sprigs in a large saucepan, and cover with water; bring to a boil. Reduce heat, and simmer 10 minutes or until potatoes are tender; drain and discard thyme.
5. While the potatoes are cooking, combine flour, salt, and pepper in a small saucepan; gradually add milk, stirring with a whisk. Stir in crushed garlic and 1 thyme sprig.
6. Place the pan over medium heat, and cook until thick (about 10 minutes), stirring constantly with a whisk.
7. Remove from heat; stir in 3/4 cup cheese.
8. Arrange potatoes and celeriac in baking dish; pour sauce over vegetables.
9. Sprinkle with 1/4 cup cheese.
10. Bake at 350 for 30 minutes or until lightly browned. Discard thyme.