Make the sablée dough

• Mix the flour, powdered sugar and salt in a bowl.
• Rub in the cold butter until sandy, then add the egg and bring together into a smooth dough.
• Flatten into a disc, wrap and chill.

Blind bake the tart shell

• Roll the dough out and line the tart pan, pricking the base.
• Bake at 180 °C until golden and crisp.
• Let it cool completely.

Cook the berry curd

• Simmer the berries with the sugar and lemon juice, then press through a sieve.
• Whisk the egg yolks into the warm berry purée and cook gently until thickened.
• Off the heat, stir in the butter until glossy.

Assemble and chill

• Pour the berry curd into the cooled tart shell and smooth the top.
• Chill until set before slicing.