Add the dark chocolate and coconut oil to a microwave-safe bowl. Microwave in 30-second intervals, stirring between each, until fully melted and smooth.
Pour the melted chocolate into the lined dish and spread evenly with a spatula. If your peanut butter is thick, gently warm it for 10–15 seconds so it’s easy to drizzle. Spoon small dollops of peanut butter all over the melted chocolate, then use a knife or toothpick to gently swirl it throughout the chocolate to create a marbled effect.
Roughly break the Kindling Sea Salt Protein Pretzels into bite-sized pieces and scatter them evenly over the chocolate along with the roasted peanuts. Gently press everything into the chocolate so it sets securely.
Sprinkle with flaky salt if desired.
Freeze for at least 30 minutes, or until completely firm. Remove from the pan and break or cut into bark pieces.
Store in an airtight container or freezer bag in the freezer for best texture.