Preheat oven to 375. Line two baking sheets with parchment paper, wax paper or tin foil. Lightly butter. Cover the bottom of the pan with both whole and broken pretzel pieces.
In a medium sauce pan over medium heat, combine the butter and brown sugar. Stir well. When the butter/brown sugar mixture begins to simmer and bubble, leave it alone and allow it to cook for 3 minutes. Do not stir! Immediately pour hot caramel mixture over the pretzels in a zig zag motion, covering most of the pretzels.
Place pan in pre-heated oven and cook for 5 minutes. Remove and place on a cooling rack. Allow to cool for 10 minutes.
While caramel pretzels are cooling, melt chocolate chips in a medium sauce pan over low heat. Once the chips are completely melted and smooth, pour the chocolate mixture over the caramel pretzels. Use a rubber spatula to gently spread the melted chocolate.
While the chocolate is still warm, sprinkle with M&M's. Finish off with a light sprinkling of sea salt.
Place pans and refrigerate for 30 minutes-1 hour.
Recipe by The Couple's Kitchen at https://thecoupleskitchen.com/christmas-treats-chocolate-toffee-bark-peanut-butter-balls/