1. Heat the olive oil in the frying pan over medium-high heat. Add garlic and fry until fragrant. Add the onion, mushroom, bacon and zucchini and cook them until soft.
2. Add all the ingredient A and saute for another 2 more minutes. Let it cool to room temperature.
3. Place a spoonful of the mixture in the center of a gyoza wrapper. Wet the edge of wrapper with fingertip. Make pleats on one side, then fold over and seal to close. Continue with the rest of the gyoza wrappers until you used all filling.
4. Heat vegetable oil in a large frying pan over medium-high to high heat. Add several gyozas (quantity depends on your pan size). Cook them until golden brown and crispy on the bottom. Add hot water (about 50ml), cover pan with the lid and let it steam over medium heat until the water evaporates. Repeat with the remaining gyoza.