In the bowl of a food processor or Thermomix, pulse together flour, a pinch of salt, sugar, and cold butter. Add cold water and pulse again. The dough should be pea-sized and resemble wet sand.
Shape the dough into a disk, cover with plastic wrap, and place in the fridge.
How to Make Apple Filling
Peel and cut apples into small cubes.
In the mixing bowl, add cut apples, brown sugar, cornstarch, and vanilla bean paste. Mix with the spatula until all is combined.
In the frying pan, add butter and let it melt. Add apple mixture and cook over medium heat for 5-10 minutes.
How to Assemble Apple Galettes
Preheat oven to 375°F (190oC).
Remove the dough from the fridge and place it on the parchment paper.
Cut into 6 equal pieces.
Using a rolling pin, make a circle from each piece of dough. Circles do not have to be perfect.
Add the apple filling into the center of the dough circle, leaving room around the edge.
Gently fold the edges of the dough over the apple filling, overlapping the dough as necessary.
In the small bowl, whisk the egg. Using a pastry brush, egg wash the edges of each galette and sprinkle with the sugar.
Bake galettes at 375°F (190oC) for 20-25 minutes or until they are golden brown.
Notes
Get all ingredients and tools ready before baking.