Line a baking sheet with parchment paper.
Break the chocolate into smaller pieces and place them in a microwave-safe bowl. Heat in the microwave in 30-second intervals, stirring in between, until fully melted and smooth.
Pour the melted chocolate onto the prepared baking sheet and spread it into an even layer, about 1/4 inch thick.
Dollop the peanut butter in small spoonfuls over the melted chocolate and gently swirl it to create a marbled effect.
Lightly sprinkle a few pinches of coarse sea salt over the top.
Place the baking sheet in the refrigerator for about 1-2 hours or until the bark is fully set.
Once set, peel the bark off the parchment paper and break it into pieces.