Set up your double boiler or microwave and melt the chopped dark chocolate slowly until smooth, stirring frequently. The chocolate should be glossy and fluid, with no lumps.
In a medium bowl, stir together the creamy peanut butter and a pinch of sea salt until well combined and slightly fluffy.
Pour the melted chocolate into the peanut butter mixture and stir thoroughly until the mixture turns thick, smooth, and homogeneous.
Cover the bowl with plastic wrap and chill the mixture in the fridge for about 30 minutes, until it firms up enough to handle.
Once chilled, use a small scoop or teaspoon to portion out the mixture and roll each into a compact ball between your palms. The mixture will feel sticky but manageable.
Place the shaped balls on a parchment-lined baking sheet, then chill again for 15 minutes to firm up.
Meanwhile, melt the additional dark chocolate in the same way as before, until smooth and shiny.
Using a fork, dip each chilled truffle into the melted chocolate, turning to coat evenly. Gently tap off excess chocolate and place back on the parchment.
If desired, sprinkle each coated truffle with coarse sea salt or chili flakes for an extra flavor boost.
Allow the chocolate coating to set at room temperature for about 20 minutes or refrigerate briefly until firm and shiny.
Enjoy these rich, fudgy truffles at room temperature for the best texture. Store leftovers in an airtight container in the fridge for up to a week.