10 ounces bittersweet chocolate chips
Line an 8 x 8" baking pan with parchment or wax paper. Cut to fit with a few inches hanging over opposite sides.
Melt 8 ounces of the chocolate chips in bowl set over (but not touching) a saucepan of simmering water (or use the microwave method). Pour and then spread the melted chocolate into the pan in an even layer. Arrange the pretzel crisps on top covering all the chocolate and pressing down gently. Freeze for 5 minutes until the chocolate has set.
Melt the peanut butter chips in the same manner as the chocolate chips (they won't be as melt-y though) and spread evenly over the chocolate and pretzels layer. Sprinkle with the peanuts and some crushed pretzels, pressing down gently again. Freeze to harden. Melt the remaining 2 ounces chocolate and drizzle over the bark.
Keep the pan in the fridge until set and ready to serve. Allow the bark to come to room temperature a bit before cutting with the sharp point of a knife.