November 17, 2021

Sweet Potato & Prosciutto Au Gratin ft. Mystic Cheese

Whether you call them scalloped potatoes or au gratin, all you need to know about this Sweet Potato & Prosciutto Au Gratin recipe is that they are a staple!

MONIQUE SOURINHO - food photographer, stylist, recipe developer, and professional taste tester. Nothing fills my cup more than connecting with like-minded people (especially over a great meal). To learn more click here.

Whether you call them scalloped potatoes or au gratin, all you need to know about this Sweet Potato & Prosciutto Au Gratin ft. Mystic Cheese recipe is that it is a new staple in my home!

The only “hard” part about this recipe is the béchamel sauce. Though there is nothing to fear! By simply keeping an eye on it during the cooking process and preventing the cream from burning you will be set on the right path! It is one of few times I do not suggest multitasking while cooking!

All you need to do is bring the cream up to temperature to help cook out the flour-y taste and to also allow the ingredients to combine so it thickens enough to become the perfect vessel for the grated cheeses to melt into. After that you give a stir, allow to blend, give another stir, then simply move right on to layering!

Everything else is less of a process, I promise!

By the way, if by any chance you wondered how this recipe developed, it stemmed from my Luscious White Veggie Lasagna recipe. After making it and thinking it tasted like a hybrid between Mac and cheese and a rich lasagna it dawned on me that the cheesy béchamel sauce probably makes a great scalloped potato recipe.

Naturally, one thing lead to another, and I went down the rabbit hole of researching the difference between scalloped potatoes versus potatoes au gratin (it’s the béchamel sauce that makes it potatoes au gratin, whereas scalloped potatoes are a little simpler. Though I can assure you, the extra steps are SO worth it.)

Preheat the oven to 350°F. In a heavy-bottomed saucepan, sauté the pancetta for 3-5 minutes over medium low, then add the onions and cook until softened about 10-12 minutes. (Add a splash of “cooking” wine or water if it sticks to the pan.) Next, add the garlic, sage, cinnamon and nutmeg. Cook until fragrant (about 1-2 minutes). Remove from heat and transfer to the bowl of potato slices.  Gently toss to coat. Set aside.

Peel the potatoes and slice into 1/4” thickness with a sharp knife or a mandoline (I prefer a mandoline since it is simpler and ensures even slices!) Transfer to a large mixing bowl.

To make the béchamel sauce, using the same saucepan, melt the butter over medium heat then stir in 1/4 cup of all purpose flour and cook, stirring constantly, until the mixture begins to bubble (about 2 minutes). Avoid letting it burn by pouring in the cream. Continue to stir. The sauce will thicken while it cooks. Allow it to gently boil then add the turmeric, sea salt and black pepper. Lower the heat, and stir in the grated cheese.  Cook and whisk for an additional 2-3 minutes or until the cheese melts thoroughly. When ready, remove from the heat and return the potato mixture.

To assemble, layer 1/3 of the béchamel sauce on the bottom of a 13″ x 10″ x 2″ casserole dish.

Next, layer the potato mixture then finish by topping with the remaining béchamel sauce. Push down any potato pieces so when it bakes it is insulated by the sauce and steam traps within to thoroughly cook the potatoes into heavenly tenderness.

Afterwards, transfer to the oven to bake for 50-60 minutes. Afterwards, increase the heat 425°F and bake for an additional 10-15 or until golden browned and fork-tender. Alternatively you can increase the heat to broil and keep an eye to avoid burning.

Remove from the oven and allow to cool for at least 15 minutes before slicing in. Alas, garnish (optional) with freshly cracked black pepper. Share and enjoy!


Sweet Potato & Prosciutto Au Gratin ft. Mystic Cheese

PREP TIME: 30 minutes
COOK TIME: 60-90 minutes
SERVES: 9

Béchamel Sauce:

  • 1/4 cup salted butter
  • 1/4 cup all purpose flour
  • 32 oz (4 cups) room temperature heavy cream (or milk)
  • 1 tsp turmeric powder (optional, for added yellow color)
  • 1 Tbs cracked black pepper
  • 2 tsp sea salt
  • 8 oz. freshly grated cheddar cheese (I prefer Mystic Cheese’s Cachalot Cheese.)
  • 8 oz. freshly grated Parmigiano-Regianno cheese (or any fuller-bodied cheese packed with umami, like Mystic Cheese’s Finback Cheese.  Mix and match and have fun! Or you can go a little more traditional with a beautiful melting cheese like gouda or gruyere!)

Assembly:

  • 3 lb. sweet potatoes, peeled and thinly sliced
  • 6 oz. prosciutto, roughly torn
  • 1 large sweet onion, diced (about 2 cups)
  • 2-3 cloves garlic (about 1 Tbs) minced
  • 4 sage leaves, thinly sliced
  • 1/2 tsp ground cinnamon
  • 1/4 tsp freshly grated nutmeg
  • Béchamel Sauce
  1. Peel the potatoes and slice into 1/4” thickness with a sharp knife or a mandoline (I prefer a mandoline since it is simpler and ensures even slices!) Transfer to a large mixing bowl.
  2. Preheat the oven to 350°F. In a heavy-bottomed saucepan, sauté the pancetta for 3-5 minutes over medium low, then add the onions and cook until softened about 10-12 minutes. (Add a splash of “cooking” wine or water if it sticks to the pan.) Next, add the garlic, sage, cinnamon and nutmeg. Cook until fragrant (about 1-2 minutes). Remove from heat and transfer to the bowl of potato slices.  Gently toss to coat. Set aside.
  3. To make the béchamel sauce, using the same saucepan, melt the butter over medium heat then stir in 1/4 cup of all purpose flour and cook, stirring constantly, until the mixture begins to bubble (about 2 minutes). Avoid letting it burn by pouring in the cream. Continue to stir. The sauce will thicken while it cooks. Allow it to gently boil then add the turmeric, sea salt and black pepper. Lower the heat, and stir in the grated cheese.  Cook and whisk for an additional 2-3 minutes or until the cheese melts thoroughly. When ready, remove from the heat and return the potato mixture.
  4. To assemble, layer 1/3 of the béchamel sauce on the bottom of a 13″ x 10″ x 2″ casserole dish. Next, layer the potato mixture then finish by topping with the remaining béchamel sauce. Push down any potato pieces so when it bakes it is insulated by the sauce and steam traps within to thoroughly cook the potatoes into heavenly tenderness.
  5. Afterwards, transfer to the oven to bake for 50-60 minutes. Afterwards, increase the heat 425°F and bake for an additional 10-15 or until golden browned and fork-tender. Alternatively you can increase the heat to broil and keep an eye to avoid burning.
  6. Remove from the oven and allow to cool for at least 15 minutes before slicing in.
  7. Alas, garnish (optional) with freshly cracked black pepper.
  8. Share and enjoy!

NOTES:

  • If there are small pools of fat at the surface take a paper towel and soak it up before serving. (I prefer to rid of excess, unnecessary fat whenever possible.)
  • Use whichever cheese best suits your taste preferences. If I can, I like to support local artisans like Mystic Cheese. For example, their Cachalot is a CT-style cheddar. Dense, creamy with complex lactic notes and evolving finish. Their Finback has bright lactic notes that give way to a lingering savory, brothy finish. Intentionally crumbly due to acidity of the curd.
  • My favorite dish to bake this in is my enameled Dansk Kobenstyle Baker Pan. Though, any casserole dish similar in size will do! I simply have a thing for oven-to-table tools haha!
  • A good mandoline is an investment. I’ve gone through a handful of cheaper ones and finally settled on taking the leap to invest in a SOLID one. Here’s the one that I recommend: Benriner Mandoline Slicer. To pair, I use cut resistant gloves (AKA stainless steel mesh gloves). There’s nothing quite like the sting of slicing yourself by accident. In this case, it’s better to be safe than sorry! That said, here is a link to the ones I use: NoCry Cut Resistant Gloves.
  • For another recipe that utilizes oven-to-table bakeware check out my Luscious White Veggie Lasagna recipe!