Cut the pineapple into pieces, keep the core.Blend it with a mixer.
Extract pulp by pouring the blended pineapple on a sieve.
Cook over medium-low heat. Stir every 5 minutes or so and more frequently towards the end to prevent burning.Add in the sugar half way into cooking (about 30 min).It is done when it is condensed enough that you can roll it into balls.
Cool the jam
Mix butter and sugar till fluffy
Sieve in flour and combine. It will be crumbly but you will be able to compact it into a ball