Pork Udon Noodles Soup (豚肉うどん)

Name: Pork Udon Noodles Soup (豚肉うどん)
Prep time: 15 min
Cook time: 10 min
Total time: 25 min
Cuisine: Japanese
Ingredients: 150g pork belly thinly sliced; 1/4 white onion cut into thin wedges; 1 tbsp shirodashi (or soy sauce); 1 tbsp mirin; 1 tsp oyster sauce; 1/2 tsp sugar; 1/2 tsp ginger paste; 50ml water; 1/2 tsp salt; 500ml dashi stock; 1 tsp sugar; 1 tsp vegetable oil; 2 portions of udon noodles; Chopped spring onion (to garnish); 4 slices kamaboko fish cakes (optional); Shichimi Togarashi (optional)