Using a pastry cutter or a food processor mix until you have rough/large breadcrumbs.
To the pastry mixture add a tablespoon at a time of iced cold water until you are able to mix it all together, using a wooden or metal spoon, to form a ball of dough.
Wrap your pastry ball in plastic wrap so it's airtight and chill in the fridge for at least an hour.
Peel and slice 500g of cooking apples and add to a bowl.
Sprinkle 2 tablespoons of golden caster sugar over the apple slices and then sprinkle a tablespooan, in total, of your chosen spices.
Give the apples a really good stir so that the sugar and spices are coating the apples and set the bowl to one side so that the sugar and spices are absorbed by the apples and they start to macerte.
When the dough has been chilling in the fridge for at least an hour transferdough on to a floured baking tray (you don't need a pie pan for this recipe) making sure it is a lightly floured surface.
Roll into a round shape. This can be quite rough, it doesn't have to be perfectly round.
Place the apple slices into the middle of the pastry. I like to lay them out on top of each other in a nice pattern in the center of the dough but make sure it's a fairly even layer.
Once the apple mixture is in place spoon the juice from the apples, with all of the sugar and spices, eon to the apples.
Leaving a 2-inch border around the edge of the pastry dough so that you can pull the edges of the galette dough up and around the galette.
It's essential that you now put the galette back into the fridge to chill for at least an hour. If you were to put it straight into the oven it would spread all over the prepared baking sheet.
Once the galette has completely chilled heat your oven to 180c.
Whilst your oven is heating up, whisk 1 egg and brush the egg mixture all over the galette crust, ensuring you don't miss the edges of the dough.
Sprinkle coarse sugar (or any brown sugar) all over the top of the egg. Don't scrimp on this part, we want a lot of sugar sprinkled on top of the dough to give us a gorgeous, flaky crust.
Bake in the oven for approximately 30 mins and until the pastry is golden brown and the bottom crust is baked through.
Dust the top of the pastry with icing sugar which is such a great way of making it look even more special without making any real extra effort. This works especially well if the galette is a gift.
Transfer to a cake stand or a pie plate and serve with custard, ice-cream or pouring cream.