Place the chocolate and butter in a bowl.
Heat the cream with the scraped-out vanilla bean, creating an infusion for around 30 minutes.
Remove the vanilla bean, bring the cream to a boil again, and pour it over the white chocolate. Let it sit for a few minutes, then mix it with an immersion blender. Be careful not to incorporate any air bubbles.
Add a bit of vanilla extract—use a high-quality one and taste to adjust. Don't add too much, otherwise you lose the delicate flavor of the vanilla bean. I like to put the vanilla bean back in to enhance the flavor further. Cover with plastic wrap. The ganache needs to set for several hours, preferably overnight, to firm up.
