Potatoes Hasselback au Gratin

Recipe Name:  Potatoes Hasselback, a version of Potatoes au Gratin

Story:  A guilty pleasure of mine are those pre-made potatoes au gratin in a box.  They are so easy to make.  But I've always wondered, surely there's a relatively easy way to make this and not be a pre-made box mix with all of that junk.  So for the past couple of years I have tried to make various versions of a Potato au Gratin.  Finally I came across this recipe, which is a play on au Gratin, but oh so good, and relatively easy!  I won't say its exactly "healthy," but it certainly is all natural.  I think I've made this at least 4 or 5 times this year alone!

Years you've been making it:  Since 2018

Author / Creator:  Original recipe by:

https://www.seriouseats.com/recipes/2013/12/hasselback-potato-gratin-casserole-holiday-food-lab.html

Submitted by:  Dustin

Ingredients:  

• 3 ounces (85g) finely grated sharp cheddar cheese
• 2 ounces (60g) finely grated Parmigiano-Reggiano cheese
• 2 cups (480ml) heavy cream
• 2 medium cloves garlic, minced
• 1 tablespoon fresh thyme leaves, roughly chopped
• 1 shallot, minced / finely diced
• 1/2 tsp paprika
• 2 tsp Kosher salt and 1 tsp freshly ground black pepper
• 3 to 3 1/2 pounds (1.4 to 1.6kg) russet potatoes, peeled and sliced 1/8 inch thick on a mandoline slicer (5 to 6 medium potatoes; see note)
• 2 tablespoons (30g) unsalted butter

Directions:  

1. Adjust oven rack to middle position and preheat oven to 400°F
2. Combine cheeses in a large bowl. Transfer 1/3 of cheese mixture to a separate bowl and set aside. 
3. Add cream, garlic, thyme, shallot, and paprika to remaining 2/3 cheese mixture. Season generously with salt (I use 2 tsp) and pepper (I use 1 tsp). 
4. Add potato slices and toss with hands until every slice is coated with cream mixture, making sure to separate any slices that are sticking together to get the cream mixture in between them.
5. Grease a 2-quart casserole dish with butter. Pick up a handful of potatoes, organizing them into a neat stack, and lay them in the casserole dish with their edges aligned vertically. 
6. Continue placing potatoes in casserole, working around the perimeter and into the center until all potatoes have been added. Potatoes should be fairly tightly packed. If necessary, slice additional potato, coat with cream mixture, and add to casserole (see note). 
7. Pour excess cream/cheese mixture evenly over potatoes until the mixture comes half way (to 2/3 way) up the sides of the casserole. You may not need all excess liquid (see note).
8. Cover tightly with foil and transfer to oven. Bake for 30 minutes. 
9. Remove foil and continue baking until top is pale golden brown, about 30 minutes longer. 
10. Carefully remove from oven, sprinkle with remaining cheese, and return to oven. Bake until deep golden brown and crisp on top, about 30 minutes longer. 
11. Remove from oven, let rest for a few minutes, and serve.

Notes:  

• I use my 9x7x3 pyrex dish, the depth of the 3" really helps, you want at least 1/2 of the potatoes covered in the cream mixture, no more than 3/4
• More recently I have done 3 oz of sharp (not extra) cheddar cheese and 2 oz of parm, this is a great combo (this is adjusted from the original recipe)
• You need the parm because it gives the sharp salty cheese flavor
• Make sure you grease the dish with butter, this really helps with cleanup
• I have found in my dish it takes 30 mins covered, then 40 mins uncovered, then 30 mins with the addtional cheese, then roughly 10 mins to cool
• The dish holds roughly 5 russet potatoes
• This recipe probably makes 6 to 8 servings, but they are great leftover and reheat in the microwave very well

Picture of the potatoes prior to baking: