Chop the pineapple into spears. Just Google 'how to cut a pineapple into spears' if you don't know how.
Put the pineapple spears into a large plastic food bag, like a sandwich bag or a freezer bag. Add the brown sugar and ground cinnamon. Shake well, secure the top and put into the fridge for at least 1 hour.
Preheat the oven to 200°c fan.
Cover a flat baking tray in foil and lightly wipe the foil with oil. Or you can use a spray oil if you prefer.
Place the pineapple onto the foil in a row and cover in the juice that's collected in the bag.
Cut the butter into small chunks and evenly scatter over the pineapple.
Put the pineapple into the oven for 10 minutes then take it out and flip the spears over. Put it back in the oven for another 10 minutes then take it out and flip it over again. Then put it back in the oven for a final 5 minutes.
At each stage you will notice that the juice has blackened more and more, it's supposed to do that becuase it's only there to keep the pineapple moist and not to eat. As long as the pineapple itself isn't black it's fine.
Serve on it's own, with vanilla ice cream like I did or in any other way that you wish to.
