In a food processor, pulse the flour and butter together, or mix by hand in a large bowl, until it resembles breadcrumbs

Add in the sugar and then the egg, and continue to combine until the dough comes together

Cover the pastry with cling film and shape into a disc about 1cm/½ in thick

Put into the fridge for an hour, or the freezer for 20-30 minutes

Make the almond paste while you wait for the pastry to chill

Put the ground almonds, icing sugar, almond extract and egg white into a food processor and combine until a thick ball of dough is formed

Turn the paste out onto a work surface and knead it a few times. Roll it into a log and wrap in cling film until you're ready to make the filling

Any unused paste will keep for a month in the fridge or 6 months in the freezer

Preheat the oven to 190ºC/375ºF/Gas mark 5

Roll out the chilled pastry on a lightly floured surface until it is about 3mm/⅛ in thick (or as thin as you can roll it before it starts to crack) and about 30cm/12in in diameter

Lift the rolled pastry into a 23cm/9in pie dish, cake tin or tart case (about 3cm-4cm/1¼ in-1½ in deep) and gently press into the sides and edges

Prepare the filling while you wait for the pastry case to cool

Put all the filling ingredients apart from the redcurrants in a food mixer

Combine until the mazarin is smooth and even, and all the ingredients have been fully incorporated

Turn the oven temperature up to 200ºC/400ºF/Gas mark 6

Pour the mazarin filling into the cooled pastry case and carefully sprinkle the redcurrants over the top, gently pushing some of them into the mazarin mixture

Bake on the middle shelf for 20-25 minutes until golden and well risen

Turn off the oven, leave the oven door ajar and allow the tart to cool slowly in the oven