Make Easter Chocolate Bark fast: glossy marbled chocolate topped with pastel M&Ms and sprinkles for festive, shareable shards.
Line a 9x13-inch baking pan with a single sheet of parchment paper, pressing the paper smoothly into the corners so the edges overhang for easy removal. Make sure the parchment lies flat against the bottom and sides with neat, tidy folds; this small prep step makes the finished bark lift cleanly and keeps the rectangular geometry sharp and consistent.
Place the semi-sweet (or milk) chocolate pieces into a large microwave-safe bowl and heat in short bursts, stirring after each burst, until the chocolate is completely melted, glossy, and velvety-smooth. Repeat the same careful short-burst melting process in a separate microwave-safe bowl for the white chocolate, stirring to a satin, pourable consistency. Work patiently so both chocolates are fluid but not scorched—smooth, shiny textures are the goal.
Pour the melted semi-sweet chocolate into the prepared parchment-lined pan and spread it evenly to the edges with an offset spatula so the base is uniformly thin and glossy. Gently pour the melted white chocolate over the dark base in ribbons and use the tip of a small paring knife or a toothpick to create soft marbled swirls—stop while the pattern still looks fresh and distinct, avoid overworking it or the colors will muddy. Rest a clean toothpick or small spatula on the rim as you admire the glossy marbled sheet and get ready for toppings.

Evenly scatter pastel-colored M&Ms across the marbled surface, then lightly sprinkle the pastel Easter-themed nonpareils or sprinkles so they nestle into the warm chocolate. Chill the pan in the refrigerator until completely set (about an hour), then lift the parchment and break the bark into irregular rectangular shards. Arrange a small stack of the broken rectangular pieces for serving so the layered marbling, glossy chocolate, and pastel candy shells read clearly in close-up.
