Heat the sesame oil in a large frying pan.
Then add the ginger, cabbage and carrots and cook for 3 to 4 minutes.
Stir in the soy sauce, chili flakes, spring onions, sesame and nigella seeds and cook until most of the liquid has evaporated.
Let the mixture cool down.
If you are using shop-bought wonton wrappers, take one wrapper and put some filling in the middle of the wrapper.
Then brush the edges of the wrapper with water, fold the dough together in a half-moon shape and pinch around the edges to seal the wrapper. Repeat with the remaining wrappers and filling.
If you are using a home-made dough, follow the recipe instructions until you have rolled out all the dough into round wrappers. Then take one wrapper, put some filling in the middle and fold the dough over into a half-moon shape; there is no need to brush the wrapper with water. Pinch the dough around the edges and repeat with the remaining ingredients.
Heat a non-stick frying pan, which is sprayed with the cooking spray, to medium-high heat and add the potstickers. Cook them until the bottom is golden brown, then add a good splash of water to the pan to create some steam and close the pan immediately with a lid.
Turn the heat down to medium and steam the dumplings for more or less 3 minutes.
Repeat until all the potstickers are cooked.
Serve with a home-made dipping sauce (check out my recipe), soy sauce or sweet chili sauce on the side. The cooking time of 5 minutes refers to one batch of potstickers.