Stir-fried Pork Belly Gochujang / korean food

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Ingredients (measure is 1 tablespoon(15ml) (1 cup: 250 ml)
marinade(sauce)
2 tablespoons of red pepper powder (60 ml)
1 tablespoon of sugar (15 ml)
1 tablespoon soy sauce (15ml)
2 tablespoons of chopped garlic (30 ml)
Black pepper (5 ml)
1 tablespoon of sesame seeds (15ml)
2 tablespoons of red pepper paste (30ml)
Water (60ml)
(Ingredients )
1/2 onion
1 spicy pepper
1/2 green onion
Pork belly (150g)
Starch water
1 tablespoon of sesame oil (15ml)