A Dariole Mould is a cylinder-shaped mould for baking or moulding.
They are shaped like a small drinking goblet or, as Alan Davidson puts it in his “The Penguin Companion to Food”, “small flowerpots.” Though usually round at the bottom, you may occasionally see them six-sided as well. They are usually taller than they are wide, but occasionally you may see squat, wide ones. All kinds will be tapering, slightly wider on top than on the bottom.
They come in varying sizes. Large ones may be 2 1/2 inches (6 cm) tall with a width at the top of 2 1/2 inches (6 cm.) Small ones may be 2 inches (5 cm) tall with a width at the top of 2 inches (5 cm.) The larger-sized ones are usually used for sweets, the smaller ones for savouries. You can buy racks for them that hold them safely upright, and allow stable resting in oven, fridge, freezer, water bath, etc.
They are made of anodised aluminium or stainless steel. They are inexpensive, but if you need one, you need several. You’d never buy just one.
The items made in them can be savoury or sweet. One of the most well-known uses for them is Coconut Madelines.
Sometimes the items in them (as in the case of mousses or jellies) are just allowed to set in the fridge, rather than being baked.
They can also be used for organizing a “mise en place”, to hold small chopped items, etc, ready to be assembled for a dish.
Not all Dariole Moulds, particularly the aluminum ones, may be dishwasher safe, so check before you buy.