Parmesan-Gruyère Potato Gratin

To save time on prep, assemble and bake this side three days ahead, then reheat at 375°F for 15 minutes.

Ingredients

• ½ stick butter
• 1 Tbs. flour
• 1 tsp. garlic powder
• 1 tsp. onion powder
• 2 cups milk
• 1 Tbs. minced fresh thyme
• 4 baking potatoes, peeled and sliced into ¼”-thick rounds 
• 1 cup grated Parmesan cheese
• ½ cup grated Gruyère cheese
• 1 bunch fresh chives, sliced

Instructions

1. Heat oven to 400°F. In pan over medium heat, melt butter. Whisk in flour, garlic powder and onion powder until smooth. Whisk in milk. Let simmer 5 min. or until thickened, whisking occasionally. Stir in thyme.
2. Spread ¼ of the potato slices in bottom of 9″x13″ greased casserole dish. Ladle ½ cup milk mixture over top; sprinkle with ¼ cup Parmesan cheese and 2 Tbs. Gruyère. Repeat layering of cream sauce, potatoes and cheese 3 times. Cover with foil; bake 1 hr., uncovering during last 10 min. Garnish with chives as desired.