Preheat oven to 400 degrees F.
Evenly arrange saltine crackers on a parchment lined baking sheet.
Heat butter and brown sugar in a saucepan over medium heat until melted and fully combined.
Boil mixture for about 5 minutes.
Carefully pour brown sugar mixture evenly over saltine crackers.
Place baking sheet in oven and bake for 5 minutes.
Distribute semi-sweet chocolate morsels over saltines and let stand for a few minutes until soft and spreadable.
While the semi-sweet chocolate is softening, melt white chocolate.
Using a spatula spread semi-sweet chocolate evenly over saltines. Then drizzle white chocolate over the saltines. Use the back of a spoons to create a swirling design.
Sprinkle crushed peppermint candy pieces over bark.
Let bark rest until completely set up. You can place the baking sheet in the refrigerator or freezer to quicken the process.
Slice or break the bark into pieces and enjoy!