What it is and where it comes from
Vanillin is the compound that gives vanilla its taste. Most is made synthetically or from wood pulp. Natural vanillin is made from rice bran by fermentation, or from clove oil by a chemical step. Vanilla sugar differs by country: in Germany and France it must contain real vanilla, and sugar with vanillin is sold as vanillin sugar. Elsewhere, vanilla sugar is often sugar with vanillin.
Where you find it
Chocolate, biscuits, ice cream, vanilla sugar, desserts and baked goods.
What to look for on the label
Powdered vanillin, vanillin sugar and vanilla sugar are halal. Liquid vanilla flavourings may be dissolved in alcohol: see alcohol in flavouring.
This is a guide, not a fatwa. Recipes change, so check the label, look for halal certification, and ask your local imam where scholars differ.