Cut off the stem base and crown, peel the pineapple and remove the eyes. Divide into four pieces, remove the stalk and cut the pineapple into rough pieces.
Dice the onion and chop the garlic finely. Preheat a pot, melt the butter and sauté the onions and the garlic until soft. Add the curry powder and the cumin and fry the spices shortly. Then put the tomato purée into the pot and let it roast for a minute or two. Add the sugar, all spice and chilli flakes and deglaze with the pineapple juice.
Bring to a boil and add the chopped pineapples. Let is simmer for about 20 minutes until the pineapples are soft. Purée with a mixer, strain the Ketchup through a sieve and bring back to a boil. Add the white balsamic vinegar and reduce the ketchup for 1-2 minutes until it has reached the desired consistency.
Let it cool down and enjoy!