For the marinade, chop the garlic and ginger very finely. Mix the sugar with the two soy sauces and dissolve in it. Add the garlic and ginger and mix well with the spices. Sprinkle the meat with the marinade and let it marinate for at least 1 hour. Turn the meat repeatedly and drizzle with the marinade. Meanwhile, for the sauce, halve the chili pepper, remove the seeds and cut into fine rings. Finely chop the spring onions as well. Mix both with fish sauce and soy sauce. Season to taste with a little lime juice. Now place the marinated meat on a grate and grill over glowing charcoal or on a barbecue so that it is still juicy inside. Remove from the grill, carve and serve with the prepared sauce.