Heat the cream until just before boiling. Add the mint leaves and lime zest, cover, and let it infuse for 15–20 minutes.
Strain the mixture, then gently reheat the infused cream.
Pour it over the white chocolate and let it sit for 1 minute, then mix until smooth and fully emulsified.
Add butter, lime juice, glucose syrup (or honey), and rum if using.
Blend with an immersion blender for a silky texture if needed.
Cover with plastic wrap in contact and refrigerate for 6–8 hours to stabilize.
