Peel and finely dice the garlic and onion. Mix lime juice, pineapple juice, fish sauce, oyster sauce, ketchup, chili sauce, vinegar and sugar. Heat oil in a pan. Sauté garlic and onion in it.
Add the sauce mixture, bring to the boil and simmer for 2 minutes until the sauce is creamy. Leave to cool a little. Wash the sparerips, dab dry and cut into pieces. Marinate in the sauce for at least 30 minutes.
Spread on a baking tray and brush with the marinade. Roast in the preheated oven (electric cooker: 200 °C/circulating air: 175 °C/gas: level 3) for approx. 30 minutes, turning from time to time. If necessary, brown in the last 2-3 minutes with the oven grill.