vanilla extract
Vanilla pods steeped in alcohol, a dark, intensely fragrant liquid used for flavouring.
Pure vanilla extract is sold in the baking aisle of most supermarkets, often next to imitation vanilla flavouring made with synthetic vanillin, which is easily mistaken for it. Larger bottles and better grades are available from health food shops, delicatessens or online.
Substitute:
The scraped seeds of half a vanilla pod replace about a teaspoon of extract and taste even finer; vanilla sugar also works but adds extra sweetness and usually only the flavour of vanillin.