Ingredients
- 2 lbs sweet potatoes peeled and sliced ⅛ inch thick on a mandoline
- kosher salt to taste
- 1 tablespoon fresh thyme roughly chopped
- 4 oz Parmesan cheese shredded
- 4 oz Gruyère cheese freshly grated
- 4 oz Sharp Cheddar cheese freshly grated
- ¼ cup milk
- 1 cup heavy cream
- 2 tablespoon butter
- 2 cloves garlic
- ¼ teaspoon nutmeg
- ¼ teaspoon red pepper flakes
- 2 shallots thinly sliced
- ½ bag Pistachios Setton Farms Tajín Seasoned Pistachios
- 2 oz Parmesan freshly grated
- ¼ cup chives thinly sliced
- Avocado oil
Method
Fry the Shallots
- Preheat the oven to 375F and lightly grease a cast iron skillet or baking dish.
- In a small saucepan, add 3 inches avocado oil over medium heat. Once hot (350–375F), add shallots and fry until just turning golden. Transfer to a paper towel-lined plate and season immediately with kosher salt.
- Set aside.
Make the Cheese Sauce
- Melt butter in a medium saucepan over medium heat.
- Add garlic and cook until fragrant (~1 minute).
- Add milk, cream, thyme, nutmeg, red pepper flakes, and salt. Bring to a gentle simmer.
- Reduce heat to low and cook 10–12 minutes to reduce.
- Remove from heat and stir in Gruyère and cheddar until smooth.
- Season to taste.
Assemble
- Sprinkle ⅔ of the fried shallots in an even layer in the baking dish.
- Add ⅓ of the cheese sauce.
- Add a layer of sweet potatoes.
- Add remaining shallots and another ⅓ of the cheese sauce.
- Add remaining sweet potatoes and top with remaining cheese sauce.
- Tap the dish gently to settle the sauce.
- Cover with foil and bake 45 minutes.
Finish
- Remove foil and bake uncovered 15 minutes.
- Pulse half a bag of Setton Farms Tajín Seasoned Pistachios in a food processor until coarse.
- Sprinkle pistachios over the gratin, followed by the grated Parmesan.
- Return to the oven for 5 minutes or broil briefly until golden.
- Rest 10 minutes before serving.
- Garnish with chives.
To Plate
- Scoop directly from the dish or slice into portions. Finish with chives.
Nutrition
Notes
Leftover sweet potato slices can be fried in the shallot oil for quick sweet potato chips.
