Unravel the pastry and use it to line a 20cm cake or pie tin with sloped sides. Trim the pastry, leaving about 2cm overhanging. Chill the pastry case while you prepare the filling. Heat the oven to 180C/160C fan/gas 4.

Beat the butter and sugar together in a bowl using an electric whisk for 2-3 mins until smooth and creamy. Add the eggs, ground almonds, lemon zest, almond extract and a pinch of salt, then beat again until combined. Remove the pastry case from the fridge and spread the jam over its base, then spoon in the almond and egg mixture, smoothing it to the edge using a spatula. Scatter the flaked almonds on top and bake for 50 mins until golden brown. Leave to cool for at least 30 mins, then dust with icing sugar and serve with cream or ice cream. Will keep in an airtight container for a few days.