Line a baking sheet with parchment paper, then arrange the pretzels in an even layer on top.

In a microwave-safe bowl, melt the semi-sweet chocolate in 30-second intervals, stirring after each interval, until smooth and fully melted.

Pour the melted chocolate evenly over the pretzels on the baking sheet. Sprinkle M&M’s and chopped peanuts evenly over the chocolate layer.

In a medium saucepan over medium heat, stir the sugar constantly as it melts. The sugar will begin to clump, then gradually transform into a smooth, amber-colored liquid. Keep stirring carefully to avoid burning.

Once the sugar is fully melted, add the butter carefully, as it will bubble vigorously. Whisk the mixture until the butter is fully incorporated.

Slowly drizzle the heavy cream into the saucepan while whisking continuously. Let the mixture come to a boil for 1-2 minutes, then remove from heat and stir in the sea salt. Set aside to allow the caramel to cool slightly.

Drizzle the prepared salted caramel over the chocolate and pretzel layer on the baking sheet. Use as much or as little caramel as desired.

Cover the baking sheet and refrigerate for several hours to set the chocolate and caramel. For a quicker set, place it in the freezer.

Once fully set, cut the bark into squares and serve.