For the onions with tamarind, first peel the onions and cut them in half. Heat the oil and fry the onions over medium heat for 20 minutes until brown all over.
Mix the tamarind pulp with 12 tablespoons of water and the sugar and deglaze the onions with it. Cover and simmer for 15 minutes. Stir occasionally, season with salt and add a little water if necessary.
Decorate the onions with tamarind with chopped cilantro.