Caramelised pineapple crumble

Everyone loves crumble. However, nowadays you seem to find that in the interests of trying to be different crumble toppings are mixed with nuts or muesli or oats, all of which are anathema to me. I like my crumble topping made with flour, butter and sugar, and that’s it. When I was in the West Indies we ate lots of pineapple, largely because it was ripened in situ, sweet as manna and delicious. The fruit you buy over here is, quite frankly, disappointing, but I hope I have found a way round