Step 1

Preheat the oven to 400˚F, grease a 9x13-inch baking pan and set aside.

Step 2

Peel the potatoes and thinly slice them using a mandoline. Then set aside.

Step 3

In a saucepan, melt 3 tbsp butter on a medium heat. Add 3 tbsp all-purpose flour and whisk for one minute until well combined. Then add 2 cups milk and whisk until all the ingredients are well combined and there are no clumps.

Step 4

Then add the seasoning (1 tsp salt, ½ tsp garlic powder, ½ tsp onion powder, ½ tsp dried oregano, ½ tsp dried thyme, ¼ tsp black pepper).

Step 5

Bring the mixture to simmer and continue cooking constantly stirring for about 10 minutes or until the sauce thickens and coats a spoon.

Step 6

When done, remove from the heat and add 1 ½ cups grated Gruyere cheese and ¼ cup grated Parmesan cheese. Fold it in until the cheese is melted and well combined.

Step 7

Take the prepared pre-greased baking pan. Evenly layer half of the sliced potatoes and pour over half of the cheesy sauce. Then layer the rest of the potatoes over and pour the rest of the cheesy sauce on top, making sure it’s all evenly spread and covers the potatoes.

Step 8

Sprinkle over the rest of the cheese (1/2 cup grated Gruyere cheese and ¼ cup grated Parmesan cheese).

Step 9

Cover with foil and bake at 400˚F for 25 minutes. Then uncover and continue baking for another 20-25 minutes or until the potatoes are tender andthe cheese gets golden/brown color.

Step 10

When done, take the baking pan out of the oven. At first, it might look like the sauce it too liquid and the butter separates. Just let it sit on the counter for 10 minutes, until the sauce sets and binds everything together.

Step 11

Serve and enjoy!