Potato and Ground Beef Gratin

Ingredients

• 1 lb ground beef 80% lean (at least )
• 1 teaspoon salt 
• 0.5 teaspoon pepper 
• 3 tablespoons butter 
• 0.3 cup onion chopped
• 3 tablespoons flour all-purpose
• 2 teaspoons thyme sprigs fresh chopped
• 3 cups milk 
• 12 oz mild cheddar cheese shredded
• 2.5 lb potatoes white peeled thinly sliced (6 cups)

Equipment

• frying pan
• sauce pan
• oven
• baking pan
• aluminum foil
• glass baking pan

Directions

1. Heat oven to 375°F. Spray 13x9-inch (3-quart) glass baking dish with cooking spray.
2. In 10-inch skillet, cook beef, salt and pepper over medium-high heat 5 to 7 minutes, stirring frequently, until beef is thoroughly cooked; drain.
3. Meanwhile, in 3-quart saucepan, melt butter over medium-low heat.
4. Add onion; cook about 2 minutes, stirring occasionally, until tender. Stir in flour. Cook 1 to 2 minutes, stirring constantly, until bubbly; remove from heat. Stir in thyme.
5. Stir milk into onion mixture.
6. Heat to boiling, stirring constantly. Boil and stir 1 minute; remove from heat. Stir in 2 cups of the cheese until melted.
7. Spread half of the potatoes in baking dish. Top with beef; spread remaining potatoes over beef.
8. Pour cheese sauce over potatoes.
9. Cover with foil; bake 45 minutes.
10. Sprinkle remaining 1 cup cheese over potatoes.
11. Bake uncovered 15 to 20 minutes longer or until top is brown and bubbly and potatoes are tender.
12. Let stand 5 minutes before serving.