Slice 600 g pork ribs into pieces.
Heat oil in a pan and sear the ribs, seasoning both sides with salt, garlic powder, onion powder, and black pepper.
Remove seared ribs to a plate.
In the same pan melt 1 tbsp butter and sauté 3 crushed garlic cloves until fragrant.
Stir in 2 tbsp tomato extract, 2 tbsp vinegar, 1 tbsp soy sauce, 1 tbsp mustard, and 2 tbsp sugar until smooth.
Lay onion rounds on foil, top with ribs, and spread the sauce over everything; wrap tightly.
Place the packet in a foil-lined pan, cover with another foil sheet and the pan lid, and cook 15 minutes.
Carefully open the foil, portion onto plates, and serve hot.