Ok so the first time I made this the potatoes weren't cooked all of the way through, and that ruined the whole thing for me and everyone else who tried it. But I believe that if it was cooked all of the way it would taste so much better. So make sure you have enough time to cook the potatoes all of the way through. This is super important so please remember.
- 3 Tablespoons Butter
- 1 Small White or Yellow Onion, Peeled and Thinly Sliced
- 4 Large Garlic Cloves, Minced
- 3 Tablespoons All-Purpose Flower
- 1 Cup Chicken Or Vegetable Stock
- 2 Cups Milk (2% or less)
- 1 Teaspoon Kosher Salt
- 1/2 Teaspoon Black Pepper
- 4 Teaspoons Fresh Thyme Leaves, Divided
- 4 Pounds Yukon Gold Potatoes, Sliced into 1/8-inch Rounds (and peeled beforehand, if desired)
- 1 1/2 Cups freshly-grated Sharp Cheddar Cheese, Divided
- 1/2 Cup freshly-grated Parmesan Cheese
- 1Preheat oven to 400 degrees.
- 2Melt Butter in a large saute pan medium-high heat. Add onion, and saute for 4-5 minutes until soft and translucent. Add garlic and saute for an additional 1-2 minutes until fragrant. Stir in the flour until it is evenly combined and saute for an additional 1-minute. Pour in the stock, and whisk combined. Add in the milk, salt, pepper, and 1 teaspoon thyme, and whisk until combined. Continue cooking for an additional 1-2 minutes until the sauce comes to a simmer (not a boil) and thickens. Then remove from heat and set aside.
- 3Meanwhile, grease a 9 x 13-inch baking pan with cooking spray. Then spread half of the sliced potatoes in an even layer on the bottom of the pan. Top evenly with half of the cream sauce, then sprinkle evenly with 1 cup of teh shredded cheddar cheese, and all of the Parmesan cheese. Top evenly with the remaining sliced potatoes, the remaining half of the cream sauce, and the remaining 1/2 cup of cheddar cheese.
- 4Cover the pan with aluminum foil and bake for 30 minutes. Then remove the foil and bake uncovered for 25-30 minutes, or until the sauce is bubbly and the potatoes are cooking through.
- 5Remove and sprinkle with the remaining 1 teaspoons thyme. Serve Warm