How to Make It
Preheat oven to 350°F. Stir together gingersnap crumbs, sugar, finely chopped crystallized ginger, ground ginger, and salt in a large bowl until well combined.
Spread pecans in a single layer in a baking pan, and toast in preheated oven until fragrant and slightly darkened, 5 to 7 minutes, stirring halfway through baking. Add pecans to bowl with gingersnap mixture; do not stir.
Stir together evaporated milk, light corn syrup, and bourbon in a medium bowl until well combined, and set aside.
Break chocolate bars into small to medium chunks. Microwave chocolate in a medium-size microwavable bowl on MEDIUM (50% power) for 30 seconds; stir. Continue to microwave until chocolate is completely smooth, shiny, and fluid, about 1 minute, stirring at 15-second intervals. To melt on the stove, bring 2 to 3 inches of water to a gentle boil in a saucepan over medium-high. Reduce heat to medium-low; maintain a gentle simmer without steam. Place chocolate in a heatproof bowl; set it over saucepan, making sure bowl does not touch water. Cook chocolate, stirring occasionally, until chocolate is melted, 2 to 4 minutes.
Add gingersnap mixture to melted chocolate, and stir once. Quickly stir in evaporated milk mixture until well combined. Cover and chill 1 hour. Roll gingersnap-chocolate mixture into about 60 (1-inch) balls. Place balls in a single layer in a large container with a tight-fitting lid or on a large rimmed baking sheet lined with parchment paper. Attach lid or cover tightly with aluminum foil; freeze until frozen solid, about 2 hours.
Melt dark chocolate melting wafers in microwave or over simmering water, as directed in Step 4. Line 2 large baking sheets with parchment paper.
Remove bourbon balls from the freezer. Drop bourbon balls into bowl of melted chocolate, and (using the tines of a fork) roll in melted chocolate until completely covered. Transfer to prepared baking sheets, and quickly and carefully garnish with sliced crystallized ginger. Chill in the refrigerator until set, about 1 hour.
Transfer bourbon balls to an airtight container, and store in the refrigerator for up to 1 week. To serve, remove from refrigerator; let stand until room temperature. Transfer to paper baking cups.