Slice the pineapple up into little pieces. Keep its juices.
Heat the vegetable oil in a small saucepan on medium heat, and add the cumin, fennel, nigella seeds, cardamoms and black pepper. Fry for a minute until you get a lovely fragrant aroma.
Add the ginger and chilli and fry for 30 seconds.
Add the pineapple and its juices and stir to coat it with the spices.
Add enough water to cover the pineapple and bring to a boil. Lower the heat right down and simmer for 15 - 20 minutes until the pineapple is soft and mushy and the water has reduced.
Add the vinegar, salt and sugar and cook for 2 - 3 until it reaches a consistency that you are happy with, depending on how much liquid you would like.
Transfer to a jar and keep in the fridge when cool. Will last for a week in the fridge.
Notes
Nutritional information is for full recipe yield (1 small jar).