Name: Sweet Potato & Prosciutto Au Gratin
Ingredients: 3 pounds sweet potatoes, peeled and thinly sliced; 6 ounces prosciutto, roughly torn; 1 large sweet onion, (~2 cups), diced; 2-3 cloves garlic (~1 tablespoon), minced; 4 sage leaves, thinly sliced; ½ teaspoon ground cinnamon; ¼ teaspoon freshly grated nutmeg; ¼ cup salted butter; ¼ cup all purpose flour; 4 cups (32 ounces) heavy cream (or milk), room temperature; 1 teaspoon turmeric powder (optional, for added color); 1 tablespoon cracked black pepper; 2 teaspoons sea salt; 8 ounces freshly grated cheddar cheese; 8 ounces freshly grated Parmigiano-Regianno cheese

Sweet Potato & Prosciutto Au Gratin

Try this twist on potatoes au gratin that puts sweet potatoes in the titular role. The only “hard” part about this recipe is the béchamel sauce. Keep your eyes on the cream during the cooking process to prevent it from burning. (This 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 taste of the flour and allow the ingredients to combine. This will thicken it enough to become the perfect vessel for the grated cheeses to melt into.

This version calls for cheddar and Parmigiano-Regianno cheeses, but you can mix and match with any fuller-bodied cheese that is packed with umami, or keep it traditional with a beautiful melting cheese like gouda or gruyere. Whatever you choose, the results will be delectable.

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Ingredients

3 pounds sweet potatoes, peeled and thinly sliced
6 ounces prosciutto, roughly torn
1 large sweet onion, (~2 cups), diced
2-3 cloves garlic (~1 tablespoon), minced
4 sage leaves, thinly sliced
½ teaspoon ground cinnamon
¼ teaspoon freshly grated nutmeg

BÉCHAMEL SAUCE

¼ cup salted butter
¼ cup all purpose flour
4 cups (32 ounces) heavy cream (or milk), room temperature
1 teaspoon turmeric powder (optional, for added color)
1 tablespoon cracked black pepper
2 teaspoons sea salt
8 ounces freshly grated cheddar cheese
8 ounces freshly grated Parmigiano-Regianno cheese

Notes

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

To make béchamel sauce, use the same saucepan to melt butter over medium heat, then stir in ¼ cup of all purpose flour and cook, stirring constantly, until the mixture begins to bubble (~2 minutes). Avoid letting it burn by pouring in cream. Continue to stir. Sauce will thicken while it cooks. Allow it to gently boil, then add turmeric, sea salt, and black pepper. Lower heat and stir in grated cheeses. Cook and whisk for an additional 2-3 minutes or until cheese is thoroughly melted. When done, remove from heat.

To assemble, layer ⅓ of the béchamel sauce on the bottom of a 13″ x 10″ x 2″ casserole dish. Next, evenly layer potato mixture atop sauce, then finish by topping with remaining béchamel sauce. Press any exposed potato pieces down into the sauce to keep them insulated during baking — this will trap steam and ensure they are tender.

Transfer to oven and bake for 50-60 minutes. Afterward, increase heat to 425°F and bake for an additional 10-15 minutes or until golden brown and fork-tender. Alternatively, you can increase the heat to broil and watch carefully to avoid burning.

When done, remove from oven and allow to cool for at least 15 minutes before slicing. Garnish (optional) with freshly cracked black pepper. Share and enjoy!

For added depth, you can caramelize the onions instead of cooking until soft. It takes more time but adds rich flavor.