Chop the chocolate. Finely chop the white chocolate and place it into a large heat-safe bowl.
Heat and infuse the cream. Measure out the total amount of cream that you'll need for the recipe, then pour ⅓ cup plus 1 tablespoon (95ml) of this cream into a 1-quart stainless steel saucepan and place the remaining cream back in the fridge until needed. Add the scraped vanilla bean seeds or vanilla bean paste to the saucepan with the cream. Place the saucepan over medium-low heat. Watch it as it comes to a simmer and do not let it simmer for long.
Make the ganache. As soon as the cream is simmering, immediately pour it over the chopped chocolate, cover the bowl and let stand for 1 minute. Uncover the bowl and whisk until the chocolate is completely melted and the mixture is smooth and silky. Let it cool for 5 minutes and then gradually pour in the remaining cold cream (260ml) in three stages while whisking until combined.
Chill the ganache. Place a piece of plastic wrap directly over the surface of the ganache, cover the bowl and place it in the fridge for minimum 6 hours, preferably overnight.
Whip it until thick and fluffy. Once thoroughly chilled, use an electric hand mixer or stand mixer fitted with the whisk attachment to whip on medium speed until thick, airy, fluffy and stiff.
