1-First, stir together the flour and a scant pinch of salt in a medium bowl. Cut the very cold unsalted butter into small cubes and work it into the flour until you get a sandy texture with pea-sized butter chunks. Gradually add the icy cold water and stir until the dough forms, then pat it into a disk, wrap it, and chill for at least 4 hours. While the dough chills, rinse and trim the strawberries, cut them into chunks, and mix them with the sugar, cornstarch, and vanilla extract.

2-Once chilled, roll out the dough into a 12-inch circle about 1/8 inch thick and transfer it to a parchment-lined baking sheet. Sprinkle the almond flour in the center, leaving a 2-inch border. Arrange the strawberry mixture on top, then fold the dough edges up over the filling to create that rustic look.

3-Prepare an egg wash by whisking the egg with 1 tablespoon water and a pinch of salt, then brush it over the dough edges. Chill the assembled galette for 30 minutes to help it hold its shape. Preheat your oven to 400°F (204°C) with a baking sheet inside, then transfer the galette to the hot sheet and bake for 35 to 40 minutes until the crust is golden. Let it cool for 15 minutes before serving, perhaps with a dusting of powdered sugar or a side of whipped cream.