All the recipes in this book use vanilla extract as it is slightly cheaper and more readily available. However, if you can find some I’d really recommend vanilla paste for an intense vanilla flavour. Use the same amount as the recipes state for extract.
Alternatively, you can use the seeds scraped from a vanilla pod if you’re lucky enough to have some in your pantry. Use half a pod for 1 teaspoon of extract. Avoid vanilla essence as it’s more processed and made using artificial ingredients.