Chop chocolate. Chop the white chocolate finely so it melts evenly.
5 oz White chocolate
Heat cream. Heat the cream until just below boiling, with small bubbles at the edges.
3 tbsp Heavy cream
Combine and rest. Pour the hot cream over the chocolate and let sit undisturbed for 2–3 minutes.
Stir smooth. Stir until fully smooth and emulsified. Optionally blend for extra smoothness.
Cool. Let the ganache cool to below 40°C / 105°F so it is warm, not hot.
Make the cream
Whip cream. In a chilled bowl, whip the heavy cream on medium speed until it doubles in volume and leaves faint trails that disappear. Stop before soft peaks.
3/4 cup Heavy cream
Add mascarpone. Add mascarpone and vanilla. Mix on low speed until smooth and lump-free.
3/4 cup Mascarpone cheese, 1 tsp Vanilla extract
Whip lightly. Increase to medium speed and whip until trails remain visible.
Add ganache. With mixer on low speed, slowly pour in the ganache, avoiding the beaters.
Finish. Scrape the bowl and mix until smooth and fully combined. The cream should be soft and spreadable.
Use or chill. Use immediately for a soft texture or refrigerate 3–6 hours for a firmer, pipeable consistency.
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Notes
Estimated yield: about 2.25 to 2.5 cups (around 540 g).