Prepare wrappers by mixing flour, cornflour and salt in a medium size bowl. Slowly add in hot water until a dough forms. You may not need all of it, or a little extra, depending on your flour. Knead for 3-4 minutes until the dough is smooth and soft. Set aside to rest for 30 mins.
Heat up a large frying pan to a medium heat with 1 tbsp oil. Prepare filling by adding onion, garlic, chilli and carrots to a food processor. Shred, dice or chop to very small pieces and add to the pan with the soy sauce. Lightly fry in the pan for 5-10 minutes, until soft and fragrant. Shred the mushrooms, cabbage and sprouts as before and add to the pan. Cook for a further 10 minutes over a medium heat. Empty filling into a bowl to cool down and wash up frying pan.
Grab a piece of dough and roll out to 1-2mm thick. Using a cookie cutter or large glass, cut out circles for wrappers. Sprinkle a little flour on each one and store on a plate until ready to use. *Freeze at this point if you won't be using them all.
Fill a small ramekin with water. Dab the edges of your wrapper with a little water. Spoon in 1 heaped tsp of filling per wrapper and carefully fold as desired to seal.
Heat frying pan with remaining oil and fry gyozas for 4-5 minutes, until brown at the edges. Serve immediately with chilli oil or soy sauce.
Recipe by Bo's Kitchen at https://www.boskitchen.com/veggiegyoza/