Here's a simple recipe for a pineapple sauce/jam. Peel a couple fresh pineapples and cut into 1-inch pieces. Put into a big saucepan. Add the juice from a lemon and a sprinkle of sugar. The amount of sugar will depend on your tastes and also on how sweet the pineapple is. Add a little apple juice, orange juice, or water-just to keep the pineapple from scorching. Cook the pineapple over medium-low heat until it is very tender, almost falling apart. Cool and then puree in a food processor or blender.
This sauce is great with ice cream, or over sponge cake, or even in crumbles or cobblers. I like to mix it with plain yogurt and granola.