Spread the M&M's and pretzels onto a parchment paper lined baking sheet.
Melt white chocolate bark according to directions.
Pour white chocolate bark over pretzels and M&M's.
Sprinkle candy cane pieces or sprinkles over top.
Let set for 10-20 minutes, til white chocolate hardens (sometimes I freeze it to quicken it up).
Break apart the bark into pieces.