Heat the heavy cream and lime zest in a small saucepan over medium heat. Stir continuously until the mixture approaches a boil, then remove it from the heat. Allow the lime to infuse the cream for 30 minutes.

Place the chopped white chocolate, lime juice, and butter in a medium heatproof bowl without stirring. Set aside to reach room temperature.

After 30 minutes, return the infused cream to the heat until it barely simmers again. Remove it from the heat and strain through a mesh sieve over the bowl of white chocolate.

Gently stir the white chocolate mixture with a rubber spatula until completely smooth. Cover with plastic wrap pressed onto the ganache surface and let it sit at room temperature for one hour, then refrigerate for 5-6 hours, or overnight.

Once chilled, scoop about 1 teaspoon of ganache, roll it into a ball, and place it onto lined baking sheets. Repeat for all filling.

Melt the bittersweet chocolate in a medium heat-proof bowl using a microwave in 30-second increments, stirring often until smooth.

Retrieve truffles from the fridge and dip each ball into the melted chocolate. Place back on the baking sheets.

Melt optional white chocolate and green candy melts to drizzle over dipped truffles, then allow to set at room temperature.