The Okinawan diet is comprised of 67 percent Okinawan sweet potatoes. These purple-fleshed sweet potatoes are rich in anthocyanins, powerful blue and purple pigments with antioxidant properties. The rich purple colour has inspired this fusion dish. It follows a classic gnocchi technique, but the purple colour and touch of miso give it an interesting twist paired with leafy spinach and shitakes.
Okinawan sweet potatoes have a beige skin and a purple interior, but they can be hard to find. A brilliant alternative is a purple sweet potato like Ben Yagi which features purple skin and purple flesh.
Be aware that, in the grocery store, produce with labels like “Japanese yams,” “purple sweet potatoes,” and “Japanese sweet potatoes” can yield vastly different results. Sometimes you’ll find purple skins hiding a white or orange interior. It’s best to ask your local produce manager, if you’re unsure, who may oblige you by cutting into one. The purple flesh will be evident quickly, and the purple colour increases once exposed to air.
Preheat oven or air fryer to 400 F (200 C).
With fork, prick sweet potato. Dip silicone brush in olive oil and baste sweet potato. Place on baking sheet and roast in preheated oven for 30 to 40 minutes, or until tender. Allow to cool completely. Remove and discard skin and, using ricer or potato masher, mash flesh. You should have about 1 cup (250 mL).
On a board, combine mashed sweet potato, flour, thyme, and salt together, kneading to combine until flour is incorporated. Form dough into one piece and then cut into 4 sections. Roll each section into a long, thin log. With knife or bench scraper, cut pieces into approximately 1/2 inch (1.25 cm) thick discs. If you have a grooved gnocchi board, you can roll each piece across it to make ridges in the gnocchi. Alternatively, use tines of a fork to make ridges in each piece of gnocchi. Make sure all pieces are well coated in flour. Repeat with remaining sections of dough.
To large bowl, add 1 Tbsp (15 mL) olive oil and set aside. To cook gnocchi, bring a large pot of water to the boil and add gnocchi. Boil for a few minutes, until gnocchi floats to surface of the water. With slotted spoon, remove gnocchi from water and add to bowl with olive oil. Toss gently to coat so it doesn’t stick together. Reserve pasta water.
In large skillet, heat 1 Tbsp (15 mL) olive oil on medium and cook garlic cloves for a few minutes. Add thyme sprigs and allow them to sizzle for 1 to 2 minutes to scent the oil. Remove garlic cloves and discard. Increase heat, add shitakes, and cook until brown. Remove and discard thyme sprigs, leaving leaves behind.
In small bowl, make a slurry with miso and about 2 Tbsp (30 mL) reserved pasta water. Add to shitakes with spinach. Keep stirring as spinach wilts. Add gnocchi and toss gently to combine, being careful not to break gnocchi.
Serve in individual bowls or on a large platter; garnish with fresh thyme leaves.