Makes 14-20; can be doubled.
1 large sweet potato
4 tsp unsweetened applesauce (homemade or store-bought)
2 fresh sage leaves, finely chopped
1/4 tsp nutmeg
1/4 tsp ground ginger
Kosher salt and fresh black pepper, to taste
14-20 wonton skins, round or square*
2 tsp peanut or canola oil
Hoisin sauce, for dipping (optional)
Prick the sweet potato with a fork, and cook in the microwave on high for 9 minutes, until very soft. Set aside to cool for a few minutes.
Scrape the sweet potato flesh into a bowl, and combine with applesauce, sage leaves, nutmeg, ginger, and salt and pepper to taste.
* If you have square wonton skins (the round ones usually are called gyoza wrappers), use a cookie cutter, pastry cutter or trace around a drinking glass with a sharp knife to create round wrappers.
Set out a small bowl of cool water, and a pastry brush.
Place one wonton wrapper in a Chinese dumpling press (or on the countertop, if you're not using a press), and place a teaspoon of filling in the center. Brush a ring of water around the entire edge of the wonton, and close the press tightly (or fold the wonton in half, and press firmly to seal the edge) to form a half-moon shape. The press will "pleat" the edge of the wonton, or you can pleat by hand, or not pleat at all.
Repeat with all of the wontons, and set aside. Have a small bowl ready with a few tablespoons of cool water.
In a large nonstick frying pan -- one with a cover, or one that can be covered by a pizza pan or baking sheet -- heat 2 teaspoons of oil over medium heat, and swirl the pan to distribute the oil over the surface. Arrange the dumplings in the pan in a single layer; they can be close together, as you won't be turning them.
Cook, uncovered, for 2 minutes, or until the bottoms are starting to brown.
Then, standing to the side so you're not over the hot oil, pour in 2 tablespoons of water, and slap the cover on the pan to trap the steam. Wait 20 seconds, lift the lid, and repeat.
Check the potstickers after the second 20-second cooking. If there is still steam in the pot or any liquid, put the cover on again for another 20 seconds. If not, add a bit more water, and cook -- the potstickers should steam for 60-90 seconds, until the wonton skins are translucent on top, and quite brown, but not burned, on the bottom.
Remove the potstickers from the frying pan, and serve warm, with some hoisin sauce drizzled on top.