Line the baking sheet: Line a rimmed baking sheet with parchment paper, leaving a bit of overhang on two sides to lift the bark out easily once it's frozen.

Mix the yogurt base: In a medium bowl, stir the Greek yogurt with honey, vanilla extract and lemon zest until smooth and evenly pale, with no streaks of honey remaining.

Spread it thin: Pour the yogurt mixture onto the lined baking sheet and spread it into an even layer about a quarter inch thick, pushing toward the edges with an offset spatula.

Melt the peanut butter: Microwave the peanut butter in a small bowl for 20 to 30 seconds, stirring halfway, until pourable and smooth.

Melt the chocolate: Melt the dark chocolate chips in a separate bowl in 20-second bursts, stirring between each, until glossy and fully smooth.

Drizzle and swirl: Drizzle the melted peanut butter and chocolate over the yogurt layer in thin lines, then drag a toothpick or knife tip through to create a marbled swirl, keeping some distinct streaks.

Add toppings: Scatter mini chocolate chips, chopped nuts and a light pinch of sea salt evenly over the top so every section has a bit of crunch.

Freeze until firm: Place the baking sheet flat in the freezer for 2 to 3 hours, until the bark is solid enough to snap cleanly when touched.

Break into pieces: Lift the frozen slab out using the parchment overhang, then break it into irregular pieces by hand or with a knife.

Store or serve: Serve the bark right away or transfer pieces to an airtight container and return to the freezer until ready to eat.