By the time one of my friends telephoned to invite my husband and me to a winter potluck dinner, I was the last one to be contacted, and most of the menu had already fallen into place.
The hosts were preparing appetizers and baking a glazed ham, another couple had promised homemade breads and dessert, and one guest had volunteered to bring a side dish of roasted tomatoes, while another had proposed a gratin of polenta with mushrooms. What was needed was a colorful and robust vegetable to serve with the ham.
After a few days, I called my friend and suggested I make mashed sweet potatoes seasoned with Parmesan cheese, rosemary and toasted walnuts. Earlier that week, while in the market, I had passed a bin filled with these copper-colored roots, and on an impulse loaded my cart with several pounds.
At home, I rejected sugar and sweet spices as seasonings and opted instead to enhance the cooked, pureed potatoes with grated Parmigiano-Reggiano cheese, crushed dried rosemary and a hint of butter. I also toasted a handful of walnuts and garnished the dish with a sprinkling of nuts and sprigs of fresh rosemary.
I relish sweet potatoes prepared this way, with savory rather than candied flavorings featured, and so did the other guests, who ate them heartily. The potatoes were a perfect accompaniment to the ham. They also would be excellent with roast chicken or turkey, or with pork chops or a roasted pork tenderloin.
Mashed Sweet Potatoes with Parmesan, Rosemary and Walnuts
3 pounds sweet potatoes, peeled and cut into 1-inch cubes
2 tablespoons unsalted butter, softened
1 1/2 teaspoons salt, plus more if needed
2 teaspoons dried rosemary, crushed (see note)
3/4 cup (3 ounces) grated Parmesan cheese, preferably Parmigiano-Reggiano
6 (2- to 3-inch sprigs) fresh rosemary, for garnish
1/4 cup toasted walnut halves, chopped (see Note)
Bring 4 to 5 quarts water to boil in large, heavy pot over high heat. Add cubed sweet potatoes and cook until very tender, about 15 minutes. Drain well in colander and then transfer to bowl of electric mixer.
Beat potatoes on medium speed until smooth. Add butter, 1 1/2 teaspoons salt, dried rosemary and Parmesan cheese. Mix well to blend. Taste and add more salt if needed.
Alternatively, potatoes can be prepared by hand. Mash well with potato masher or wooden spoon and then stir in seasonings. (Potatoes can be prepared a day ahead. Cool, cover and refrigerate. Reheat in microwave-proof dish in microwave or place in baking dish, cover with aluminum foil and reheat in oven at 350 degrees until hot, about 15 minutes or longer.)
To serve, mound potatoes in shallow serving dish or bowl. Place cluster of fresh rosemary sprigs in center and sprinkle with walnuts.
Note: It is important to crush dried rosemary finely for this recipe. Either crush in mortar with pestle or place in plastic bag and crush with rolling pin.
To toast walnuts, place on rimmed baking sheet. Bake on center shelf at 350 degrees until lightly browned and fragrant, about 8 minutes. Watch carefully, then remove and chop.