Pineapple tart pastry is a shortcrust pastry or biscuit pastry with a high fat content (from butter). As with pie pastry, chilling helps the butter in the dough firm up, allowing the filled pineapple tarts to hold their shape better during the baking process. Also, chilling gets the butter into a nice, cold form so that it melts immediately in a hot oven. This allows the tarts to bake up flaky and crisp. Letting the dough sit at room temperature (especially in a warm environment like our tropics) for too long will cause some of the butter to melt and release water prematurely before it hits the oven. Please note that you will need to add a few minutes of baking time when baking tarts that have had a good chill.