• Place chocolate and butter in microwave-safe bowl and heat for 30 seconds. Stir and heat for another 30 seconds; set aside.
• In small saucepan, heat cream, ginger and salt over medium heat until small bubbles form around edge of pan. Pour over chocolate; let stand 30 seconds before stirring until smooth.
• Line 8-in (20-cm) baking dish with plastic wrap, leaving enough overhang to cover top. Scrape chocolate mixture into prepared pan and cover with overhang, pressing down lightly. Refrigerate until firm, 1 to 2 hours.
• Line baking sheet with parchment paper. Using a 1 tbsp measuring spoon, scoop chocolate, gently roll each to form a ball and drop onto prepared pan. Refrigerate until firm, 15 to 30 minutes.

Coating:

• In microwave-safe bowl, heat two-thirds of the chocolate in 30-second bursts, stirring well after each interval until three-quarters has melted. Stir until smooth and fully melted.
• Add remaining chocolate and stir until mixture is smooth and melted. The chocolate doesn’t need to be perfectly tempered for truffles. Test the temper by dipping an offset spatula or plastic scraper into the chocolate and then refrigerating it on a plate until firm; the chocolate should be shiny and should snap when broken.
• Using 2 forks, dip each truffle into chocolate-coating mixture, tapping fork on edge of bowl to remove excess; return to pan and top with crystalized ginger (if using). Let set and serve.