A thin crunchy biscuit, often made with almond flakes (tuiles aux amandes) or coconut, that you often get with creamy desserts. Some are curved before baking to resemble the Roman roof tiles.
Very thin lacy ones (tuiles dentelles) can be savoury as well as sweet, and at that certain je ne sais quoi to a dish.
Images by chef theirry, La Sariette