Dumplings with a sweet & sour cabbage-mushroom filling and chili broth on top

INGREDİENTS

• 2 tbsp. canola oil or sesame oil
• 1 small onion, chopped
• 3 cloves of garlic, minced
• A ca. 2 cm long piece of ginger, peeled and finely chopped
• 1/2 small head of cabbage, finely chopped
• 1 spring onion, finely chopped
• 200g mushrooms  finely chopped
• 1 tsp. salt
• 1 1/2 tbsp. flour
• 1 tbsp. dark soy sauce
• 1 tbsp. apple cider vinegar
• 2 tbsp. brown sugar