Line a 9×13-inch pan with parchment paper, leaving an overhang for easy removal.

Fill a saucepan with 1–2 inches of water and bring to a simmer over medium heat. Place bittersweet chocolate and 1 tablespoon coconut oil in a heatproof bowl set over the pan. Stir until melted and smooth, about 3 minutes.

Remove bowl from heat; whisk in orange extract until well combined.

Pour chocolate into prepared pan and spread evenly. Tap pan firmly on the counter a few times to release air bubbles. Refrigerate until set, about 10 minutes.

Clean and dry the bowl. Place white chocolate and remaining 1 tablespoon coconut oil in the bowl over simmering water; stir until melted and smooth, about 2 minutes.

Remove from heat; stir in orange extract or orange zest.

Drizzle melted white chocolate over the dark layer in a zigzag pattern. Use a toothpick to drag through chocolate and create a marbled effect.

Sprinkle candied orange peel over the top. Refrigerate until completely set, at least 2 hours or overnight.

Use parchment overhang to lift chocolate out of pan. Peel away paper and cut chocolate into 1×4-inch sticks with a sharp knife, wiping the blade between cuts for clean edges.