MAKE THE PASTRY: To make the pastry, place the butter, flour, salt and sugar in the bowl of a food processor with the blade fitted and process on high until the mixture resembles fine breadcrumbs. Pour in the beaten egg, then run the processor until the mixture clumps together and forms a soft dough. This takes longer than you might think, up to a minute or so. If the dough refuses to come together add a little cold water a teaspoon at a time until it does.

ROLL AND CHILL: Turn the dough out onto a lightly floured surface, knead into a ball, then use a rolling pin to tap it out into a disc. Roll out to a round larger than the tin, dusting with flour and turning as you go. Place the dough into the tin, pressing it gently but firmly into all the corners. Fold the overhanging pastry back into the tin to create a firm edge. Prick all over with a fork, then place in the freezer for 15 minutes, or the refrigerator for 30. Keep the pastry trimmings aside.

MAKE THE CUSTARD: Meanwhile, heat the oven to 200°C / 400°F / Gas 6. Prepare the filling by beating together the eggs, creme fraiche, sea salt, garlic, paprika powder and parsley with a few grinds of black pepper. Set aside to infuse.

BLIND BAKE: When the pastry has chilled, remove from the freezer or fridge, scrunch up a sheet of baking paper and use it to line the pastry. Line the baking paper with a piece of foil, pressing to the shape of the pastry. Place the tart tin on a baking tray, then blind bake (see FAQ'S) for 15 minutes. Remove the foil and baking paper and bake for a further 5 minutes.

CHECK THE TART SHELL: Remove the tray from the oven and reduce the heat to 180°C / 350°F / Gas 4. Check the pastry case for any cracks - if so, dampen a small amount of pastry trimmings with a little water so it has a paste-like consistency and very carefully use this to plug any holes or cracks. Brush the tart shell with mustard, be gentle as the pastry is still fragile.

FILL AND BAKE: Scatter over the spring onions, pour in the egg mixture, then tear the salmon into pieces and place add to the tin. Bake in the preheated oven for 40-45 minutes until puffed in the middle and golden.

REST AND ENJOY: Allow the quiche to cool to room temperature on a rack before cutting.