Make the Pastry
In a stand mixer with a paddle attachment, cream the softened butter and icing sugar on medium speed until smooth (about 2 minutes).
Add the egg and half of the flour, mixing on low speed until combined.
Remove the bowl from the mixer and mix in the ground almonds and remaining flour by hand. Avoid overworking the dough.
Shape the dough into a disc, wrap it in cling film, and refrigerate for 30 minutes to 2 hours.
Roll Out and Line the Tart Tin
Roll the chilled pastry between two sheets of baking parchment to about 3 mm (⅛ inch) thickness.
Line a 25 cm (10-inch) tart tin with the pastry, pressing it into the edges. Trim the excess, leaving a slight overhang.
Prick the base with a fork and refrigerate for at least 15 minutes.
Blind Bake the Pastry
Preheat the oven to 180°C (350°F).
Line the pastry with baking parchment and fill with baking beans or pie weights.
Bake for 15 minutes, then remove the parchment and weights. Bake for an additional 5–7 minutes until golden.
Prepare the Lemon Filling
In a large mixing bowl, whisk together the eggs and caster sugar until smooth.
Add the double cream, lemon zest, and lemon juice, whisking until well combined.
Slowly stir in the melted butter to create a rich, silky filling.
Assemble and Bake
Reduce the oven temperature to 160°C (320°F).
Pour the lemon filling into the pre-baked pastry shell.
Bake for 25–30 minutes, or until the filling is set with a slight wobble in the center.
Cool and Serve
Let the tart cool completely in the tin before removing it.
Dust with icing sugar before serving for a decorative touch.
