Remove the flaky pie crust from the fridge or freezer to come up to room temperature as instructed on (to prevent cracking).

Combat marzipan frangipane ingredients in the bowl of a food processor or blender, and blitz until you get a smooth paste. Set aside until needed.

Cut the apple quarters (skin on) into 3mm slices, keeping the slices grouped together in their quarters. Pour over the lemon juice (to prevent oxidation and browning) and set aside until needed.

On a lightly floured piece of baking paper, roll out the flaky pie crust to 3mm thick and cut out a 30cm circle.

Spread the frangipane in an even layer on top, leaving a 5cm border around the edge.

Arrange the sliced apple quarters on top of the frangipane, crowding them closely together.

Fold the pastry border over the apples and press down gently to seal.

Trim the excess baking paper and transfer the galette, together with the baking paper, on to a large baking sheet.

Refrigerate for at least 15 minutes.

Adjust the oven shelf to the middle position and preheat the oven to 390F.

Brush the chilled pastry with the whisked egg, sprinkle the galette with the flaked almonds and granulated sugar, and bake for 45-50 minutes or until the pastry is deep golden brown and crisp.

Using a large offset spatula, very carefully lift the pastry to check the bottom - it should be golden brown too.

If the pastry starts browning too quickly, cover the galette with foil (shiny side up) and bake until done.

Cool on the baking sheet for 10-15 minutes, then transfer to a wire rack to cool completely.

Best on the day, but you can keep it lightly covered with kitchen paper for up to 2 days.

Don't use a closed container as that would soften the crust.