Instructions

• Preheat the oven to 200°C / 400°F. Roll the 300g sweet shortbread dough between two sheets of baking paper until large enough to line four 5-inch tart tins. Line the tins with the pastry, trim the edges, then cover and refrigerate for 30 minutes.
• Remove the chilled tart tins from the fridge. Prick the pastry bases several times with a fork to prevent bubbling. Place the tins on a baking tray, line the bases with baking paper, and bake for 10 minutes. Remove the paper and continue baking for a further 8–12 minutes, or until the pastry is lightly browned. Remove from the oven and allow the tart shells to cool completely.
• While the pastry cools, make the chocolate ganache. Put the 100g dark chocolate chips in a heatproof bowl. Heat the 100ml double cream until hot but not boiling (steam rising, small bubbles at the edge). Pour the hot cream over the chocolate, let sit for 1 minute, then stir gently until smooth and fully combined. Stir in the zest of one orange (the zest listed under the ganache).
• Let the ganache cool for a few minutes until it is thickened but still pourable.
• Spread the 4 tablespoons of orange marmalade evenly across the base of the four cooled tart shells (about 1 tablespoon per tart). Spoon or pour the cooled ganache over the marmalade, dividing it evenly among the tarts.
• Chill the filled tarts in the refrigerator for about 10 minutes to set the ganache. Sprinkle with the remaining zest of one orange and serve.