Pour your milk chocolate baking chips in a microwave safe bowl and melt according to the instructions on the bag or in 30 second incremements. Repeat the same steps with your peanut butter baking chips. While the milk chocolate is still hot, spread evenly on a silpat baking sheet or piece of parchment paper. Layer your melted peanut butter chips on top of the milk chocolate and slowly mix the two chocolates together. Top with the crushed protein pretzels. Place in the refrigerator for 20 minutes or until completely hardened. Once hardened remove chocolate from silpat and break into bite sized pieces.