Prep: Line an 8×8-inch baking pan with parchment paper, leaving an overhang for easy lifting later. Lightly spray with nonstick cooking spray.

Melt dark chocolate: Melt the dark chocolate. Stir in ¼ teaspoon oil, half of the peppermint extract (⅛ teaspoon), peppermint dust (1–2 tablespoons), and a small pinch of sea salt.

Assemble dark chocolate layer: Spread the dark chocolate evenly in the prepared pan. Chill 10-15 minutes in the fridge — just until set but still slightly tacky.

Melt white chocolate: Melt the white chocolate and let it cool until just warm (around 85–90°F). Stir in the remaining ½ teaspoon oil, ¼ teaspoon extract, and, if desired, 1–2 tablespoons of medium peppermint pieces for a “confetti” look (fold the peppermint pieces in last, and do it quickly, or else your white chocolate may turn pink).

Assemble white chocolate layer: Gently spread the white chocolate over the first layer. (If the dark layer got too cold, rest it 5 minutes at room temperature first. Spread the white chocolate quickly and try not to disturb the dark layer).

Decorate & chill: Sprinkle the remaining larger peppermint pieces over the top and press lightly so they stick. Chill 30–60 minutes, or until firm.

Finish: Lift the bark from the pan. Let stand 10 minutes at room temperature, then cut into squares with a warm, dry knife (wipe after each cut for extra-clean slices). Store in an airtight container for up to 2 weeks – best kept chilled.