Japanese sweet potatoes have purple skin, creamy white flesh and a sweet, almost-floral flavor. They are starchier than other sweet potatoes, making them perfect for this twist on classic gnocchi. If you are unable to find them, substitute 1 lb. (500 g) orange-fleshed sweet potatoes and 1 lb. (500 g) russet potatoes.
White Sweet Potato Gnocchi with Hazelnut Pesto
- 2 lb. (1 kg) Japanese sweet potatoes
- 2 cups (10 oz./315 g) unbleached all-purpose flour, plus more for dusting
- 1 egg
- Fine sea salt
- 1 cup (5 oz./155 g) toasted and skinned hazelnuts
- 2 cups (2 oz./60 g) fresh flat-leaf parsley leaves
- 1 tsp. finely grated lemon zest
- 1/2 cup (4 fl. oz./125 ml) extra-virgin olive oil, plus more if needed
- 2 Tbs. hazelnut oil (optional)
- 1/2 cup (2 oz./60 g) freshly grated Parmesan cheese, plus more for serving
1. Put the sweet potatoes in a large pot and add water to cover by 2 inches (5 cm). Bring to a boil over high heat, then reduce the heat to medium-high and cook until tender, about 30 minutes. Drain well. When cool enough to handle, peel the potatoes and cut in half.
2. Press the potatoes through a potato ricer directly onto a lightly floured work surface to form an airy mound. Let cool slightly. Sprinkle 1 3/4 cups (8 1/2 oz./265 g) of the flour around the mound. Make a well in the mound and add the egg and 3/4 tsp. salt. Using a fork, whisk the egg and begin to incorporate the potatoes, eventually incorporating the flour. Use a dough scraper to gather up any sticky bits of dough. Sprinkle the remaining 1/4 cup (1 1/2 oz./45 g) flour over the dough and very lightly knead until it forms a soft, shaggy ball. It should feel slightly tacky but not sticky. Gently move it to the side and cover with a kitchen towel.
3. Dust a work surface and 2 rimmed baking sheets with flour. Cut off a tangerine-sized piece of dough and gently roll into a rope about 3/4 inch (2 cm) in diameter. Cut into 1-inch (2.5-cm) lengths. Roll each gnocchi down the curved tines of a fork or down the length of a gnocchi board to create an indentation on one side and grooves on the other. Place on a prepared baking sheet. Repeat with the remaining dough. You should have 150 to 175 gnocchi. If not cooking them right away, place the baking sheets in the freezer until the gnocchi are firm, at least 1 hour. Then transfer to airtight containers and freeze for up to 1 month. Cook directly from the freezer.
4. Bring a large pot of salted water to a boil over high heat. In a food processor, combine the hazelnuts, parsley, lemon zest and 1 tsp. salt. Pulse to break up the nuts and parsley leaves. With the motor running, drizzle in the olive oil and hazelnut oil, if using, until a coarse paste forms. Add more olive oil if needed to achieve a thick, pourable consistency. Scrape the pesto into a bowl and stir in the cheese. Spoon a little of the pesto into a warmed large serving bowl.
5. Add half of the gnocchi to the boiling water and cook until soft and fluffy but cooked through, 3 to 5 minutes. Using a skimmer, transfer them to the serving bowl and toss gently with the pesto, adding a splash of the cooking water to loosen the sauce, if needed. Cover to keep warm. Repeat to cook the remaining gnocchi and transfer to the bowl. Spoon on more pesto and toss gently (reserve any leftover pesto to toss with spaghetti). Sprinkle with a little cheese and serve. Serves 8.
Find more recipes like this one in our enticing collection of authentic dishes made modern, Rustic Italian, by Domenica Marchetti.