Put your vanilla beans on a baking dish and bake in a 100°C or 212°F fan forced oven for 1 hour or until dried out. Alternatively, you can use the dehydrator or put in the freezer for 3 days.
Allow to cool completely, then break into chunks.
Put into your mixer bowl, mill for 1-2 min/speed 9/MC on.
Store in an airtight container.
Notes
Because this is pure vanilla bean powder, you only need half the quantity of powder as a substitution for liquid or paste.