Set up a double boiler by placing a heatproof bowl over a saucepan of simmering water. Add chopped dark chocolate to the bowl and melt, stirring gently until smooth and glossy, about 3-5 minutes. The chocolate should be silky and fragrant.
Remove the bowl from heat, then stir in unsalted butter and vanilla extract until fully incorporated and shiny. Let the mixture cool slightly for about 5 minutes, until it thickens just a bit but remains pourable.
In a separate bowl, combine the creamy peanut butter and powdered sugar. Mix until smooth and well blended. This will create a thick, sticky mixture.
Pour the slightly cooled melted chocolate into the peanut butter mixture and fold together until you get a uniform, thick dough that’s easy to handle.
Using a small scoop or teaspoon, portion out about 1 teaspoon of the mixture and roll it between your palms to form a smooth ball. Place each ball on a parchment-lined tray as you go.
Refrigerate the formed truffles for about 30 minutes, or until they are firm and set. If your mixture feels too soft, pop the tray in the freezer for 10 minutes to speed up the process.
While the truffles chill, melt the remaining dark chocolate in a clean bowl using the same double boiler method, stirring until smooth and glossy.
Using a fork or toothpick, dip each chilled truffle into the melted chocolate, turning to coat completely. Let excess chocolate drip off before placing the coated truffle back on the parchment-lined tray.
Refrigerate the dipped truffles for another 15 minutes or until the chocolate coating is set and shiny. They are now ready to enjoy or gift!