Peel, wash and chop the potatoes, cover and cook in salted water for 15-20 minutes. Peel and finely chop the onion. Knead with minced meat, egg, breadcrumbs, salt and pepper. Form into 12 meatballs. Simmer in boiling salt water for about 10 minutes.
Clean the chilli, cut lengthwise, remove seeds, wash and cut into rings. Boil pineapple pieces, up to 3 tablespoons, with juice and coconut milk, puree. Thicken with sauce thickener. Season with salt and pepper. Heat the rest of the pineapple and chilli in it.
Wash the coriander and remove the leaves. Drain potatoes and meatballs. Serve with the coconut sauce. Sprinkle with coriander.