Chef Tune's Sweet Onion & Potato Au Gratin

The perfect side dish for any holiday gathering! Food Network Chopped Champion Shannen Tune shows you how to make a delicious and simple sweet onion & potato au gratin casserole.

  • 4 - 5 Russet potatoes, sliced 1/4" thick
  • 2 RealSweet sweet onions, sliced and caramelized  
  • 2 cups whole milk
  • 16 oz cheddar jack cheese, shredded
  • 2 T all-purpose flour
  • 2 T unsalted butter
  • 2 T ground Parmesan cheese
  • Salt & pepper to taste


  1. Place sliced potatoes in a pot and cover with cold water. Bring water to a boil and cook for 5 minutes. Drain water and cool potatoes.
  2. In a small saucepan melt butter and add flour to make a roux. Mix until it looks like wet sand. And one cup of milk to roux and whisk together. After milk and roux are mixed and the milk is warm add the rest of the milk and season with salt and pepper. Allow sauce to simmer for 20 minutes and stir continuously so that it doesn’t burn.
  3. Spray the baking dish with nonstick spray and layer half of the potatoes. Top the first layer of potatoes with caramelized onions and half of the cheddar-jack cheese. Layer the cheese with the rest of the potatoes, then top with the bechamel sauce, parmesan cheese and the rest of the cheddar-jack cheese.
  4. Bake in preheat oven at 350 degrees for 25 minutes of until the cheese begins to bubble and brown. Allow to cool before cutting it. 

Prep Time

15 minutes

Cook Time

25 minutes

Tags: Dinner