Line a 15 x 11 cookie sheet with wax or parchment paper and set aside.
Add the white chocolate and vegetable oil to a double boiler. Melt over medium heat, stirring occasionally. Remove from heat and stir.
Pour the melted white chocolate onto the cookie sheet. Use a spatula to spread the chocolate out evenly.
Immediately sprinkle the broken pretzel pieces, white chocolate peanut butter cups and red and green M&M candies on top of the melted chocolate. You will want to complete this step fast before the chocolate hardens.
Chill for 30 minutes to allow the bark to completely harden.
Once hardened, remove the bark from the refrigerator and set aside. Place the peanut butter in a microwave safe bowl and microwave on HIGH for 20 seconds or until melted. Allow to cool and thicken for 5 minutes.
Drizzle the peanut butter on top of the candy bark and chill again for 30 minutes to help the peanut butter solidify.
Before serving, break bark into pieces and ENJOY!
*Store in an airtight container in the refrigerator for up to one month.