In a bowl, combine the apple slices, brown sugar, flour, cinnamon powder, and lemon juice, and mix together until the apples are fully coated. Let the filling chill in the fridge for 10-15 minutes while you roll out the pastry dough.
300 gs (about 2) apples, peeled and sliced, 50 gs packed brown sugar, 12 gs all-purpose flour, 2 tsps lemon juice, 1.5 tsp cinnamon powder
Pre-heat the oven to 180 degrees Celsius.
To roll out the pastry dough, place it in between two baking sheets, then roll it to 2-3mm thickness. Cut the edges on the dough to create a roughly clean oval shape, then place the apple slices in the center of the dough, leaving a 1-2 inch empty border on the edges. Make sure you are not adding the excess liquid from the apple to the dough. Fold the edges of the pie dough inwards towards the filling like you would a piece of cloth. Don't worry about making it too pretty, a galette is supposed to be rough. Make sure all the corners are sealed properly.
Brush the pastry with the egg wash and sprinkle granulated white sugar on top. Bake the pie until the crust is golden brown and the filling is bubbling. If the bottom of the pie starts to get dark before the top has baked properly, switch off the bottom burner and turn on the top burner of the oven.
1 egg mixed with a splash of milk, Granulated sugar
Make the apple caramel: while the pie is baking, add the remaining apple liquid from the filling (you can adjust the measurement based on the amount of reserved apple liquid you have remaining from the filling) to a saucepan and cook it for 2 minutes until it thickens. Add the butter and whisk until it's properly incorporated into the syrup, then add the whipping cream and whisk until properly combined. Top the pie with the apple caramel as soon as it comes out of the oven so that it melts into the filling from the heat.
100 ml reserved apple liquid from the filling, 20 gs unsalted butter, 50 ml liquid whipping cream
Top the warm apple galette with ice cream and enjoy!