In a food processor, blend 1 ½ cups of plain flour, ½ cup of icing sugar, and a pinch of salt until combined. Cut in ½ cup of very cold unsalted butter until the mixture resembles fine crumbs. Add 1 egg and pulse until the dough starts to come together. Turn the dough onto a floured surface, shape it into a disk, wrap in plastic, and refrigerate for at least 1 hour.

Preheat your oven to 160°C (325°F). Roll out the chilled dough to about ¼ inch thick and cut out circles to fit your muffin pan. Gently press the rounds into the pan and prick the bases with a fork. Freeze the shells for about 15 minutes, then bake with weights (like dried beans) for 15 minutes. Remove weights and bake for another 15 minutes, or until the edges are golden brown.

In a medium saucepan, whisk together ½ cup of fresh orange juice, the zest of 1 orange, 4 egg yolks, ¾ cup caster sugar, and 2 tablespoons of cornstarch. Heat gently over low-medium heat, stirring constantly until the mixture thickens and coats the back of a spoon—about 5-7 minutes. Remove from heat and stir in 2 tablespoons of cubed butter until smooth. Strain if necessary for a silky texture.

Pour the warm orange curd into the cooled tartlet shells, filling them about three-quarters full. Place the filled tartlets in the refrigerator and chill for about 2 hours, or until the curd is fully set and firm to the touch.

While the tartlets are chilling, chop 200g of dark chocolate and place it in a heatproof bowl. In a small saucepan, heat ½ cup of heavy cream until it just begins to simmer. Pour the hot cream over the chocolate and let it sit for 5 minutes. Stir gently until the mixture is smooth and glossy.

Once the curd has set, carefully pipe or spoon the chocolate ganache over each tartlet, covering the orange curd completely. Allow the ganache to set for 1 hour at room temperature.