Chestnut flour gives these otherwise standard potato gnocchi a nutty and slightly bittersweet flavor that becomes mellow and fragrant when they are smothered in a walnut sauce. This particular walnut sauce is a plain white sauce (besciamella) flavored with fresh walnut paste. Peeling the membranelike skins off the walnut halves takes a couple of minutes, but it is well worth the extra effort and creates a sweeter sauce.
Chestnut flour is made from small garessina chestnuts, which are quite different from the larger, more common marroni chestnuts. It is a seasonal flour that is mostly available in the winter and is best kept in the freezer because of its high fat content.
- 1 cup raw walnut halves
- 4 garlic cloves, chopped coarse
- ¼ cup olive oil
- 1½ tablespoons unsalted butter
- 2 tablespoons unbleached all purpose flour
- 1¾ cups milk
- ½ teaspoon salt
- ¼ teaspoon freshly ground black pepper
- ¼ cup coarsely chopped fresh marjoram leaves
- ½ cup freshly grated Parmesan cheese
- 3 medium baking potatoes, such as russet
- ¾ cup chestnut flour
- ½ cup unbleached all purpose flour, plus some extra for dusting
- 1 teaspoon salt
- Potato ricer
- Gnocchi board (optional)
- Large plate or tray to hold the dumplings cooked in batches
1. Prepare the walnuts: fill a small saucepan halfway with water and bring to a boil over high heat. Reduce the heat to low for a gentle simmer. Add the nuts and simmer for 10 minutes. Remove the nuts from the heat, drain, and run under cold water until cool. Peel off the skins as best you can. (We found starting in the center of the nut made it a little easier.) Place the peeled nuts in a bowl and set aside.
2. Make the dough: place the potatoes in a small pot, pour in enough water to cover, and bring to a boil over high heat. Cover, reduce the heat to medium, and simmer until fork-tender, about 30 minutes. Drain and place the potatoes on a folded kitchen towel. Once they are cool enough to handle, peel off and discard their skins, break them into chunks, and then press through the ricer into a large bowl.
3. Combine the flours in a small bowl. Scoop out ¼ cup and set aside. Add the 1 teaspoon salt and the remaining flour mixture to the potato. Toss with your fingers until mixed evenly. Drizzle in 1/3 cup water and work the dough with your hands into one manageable ball. If the dough is too wet and sticky, work in some of the reserved flour mixture, a little at a time, until it no longer sticks to your fingers. Knead the dough in the bowl for about 1 minute. The dough will be soft and slightly sticky.
4. Make the dumplings: Line a tray with a kitchen towel and sprinkle with a little flour.
5. Knead the dough once or twice on a floured surface, divide it into 8 equal pieces, and set 7 of them aside under a kitchen towel. Roll the remaining piece of dough into a rope about ½ inch thick. Cut the rope into ¾-inch lengths.
6. If you don’t want ridges on your gnocchi, place the cut dough pieces on the prepared tray in a single layer. If you do want ridges, roll each piece along the gnocchi board or along the tines of a fork. Roll the piece along the back of the fork to avoid catching it on the ends of the tines. Arrange the gnocchi in one layer on the prepared tray. Repeat with the remaining dough.
7. Cover and place the tray of dumplings in the refrigerator while you make the sauce. Set aside the number of dumplings that you would like to cook and keep the rest frozen for up to 6 months.
8. Make the sauce: Fill a large pot halfway with salted water and bring to a boil over high heat. Once it comes to a boil, reduce the heat to low for a gentle simmer.
9. Meanwhile, pulse the walnuts and the garlic in a food processor until the walnuts are well broken apart. Continue to process while slowly drizzling in the oil until the mixture becomes a thick, grainy paste. Scrape down the sides of the processor bowl and scoop the paste into a bowl.
10. Melt the butter in a medium pot over low heat, add the 2 tablespoons flour, and stir continuously for 3 minutes. Pour the milk in slowly, whisking constantly. Once the mixture is smooth, raise the heat to medium and bring to a simmer. Mix in the walnut paste, ½ teaspoon salt, and the pepper and simmer for 1 minute longer. Cover and reduce the heat to very, very low to keep the sauce warm while cooking the gnocchi. (You can also make the sauce up to 3 days in advance and keep it refrigerated in a tightly sealed container.)
11. Cook the dumplings: Bring the water back to a boil over high heat, then reduce the heat to medium for a steady simmer. Carefully drop a few dozen gnocchi, a few at a time, into the water. Cook until the gnocchi float to the surface of the water, about 2 minutes, then cook for 2 minutes longer. (If cooking frozen gnocchi, add them directly into the simmering water and increase the cooking time by 1 minute. Do not allow the gnocchi to thaw before cooking.)
12. Remove the gnocchi with a slotted spoon, scatter them on the large plate or tray, and drizzle with a few spoonfuls of the cooking liquid to prevent sticking. Resting the cooked gnocchi on a roomy plate prevents them from piling up on each other while they set and firm up a bit. Cook the remaining gnocchi and place them on the plate with another few spoonfuls of the cooking liquid. Set aside ½ cup of the cooking liquid for the sauce.
13. Once all the gnocchi have been cooked, return the sauce to a simmer over medium heat. Drain the gnocchi, mix them into the sauce, and cook for 1 minute to warm through. If the sauce is a little thick, stir in some of the reserved cooking liquid. Remove from the heat, stir in the marjoram and the Parmesan, and serve.
Nutritional information is based on 6 servings.