1. In a large bowl whisk flour, sugar and salt.

2. Cut cold butter into the flour until mixture resembles coarse crumbs.

3. Stir in sourdough starter and add cold water as needed to form a rough dough.

4. Shape dough into a disk, wrap and chill for at least 1 hour.

5. On a floured surface roll dough into a 12-inch circle and transfer to a parchment-lined baking sheet.

6. Rinse, hull and slice strawberries.

7. In a bowl toss strawberries with brown sugar, cornstarch, lemon juice, vanilla and salt and let sit 10 minutes.

8. Mound strawberries in the center of the dough, leaving a 2-inch border.

9. Fold the edges of the dough up over the filling, creating rustic pleats.

10. Brush the crust with beaten egg and sprinkle coarse sugar.

11. Bake at 400F for 35-45 minutes until golden and bubbling, covering edges with foil if browning too quickly.

12. Let galette cool on a rack for 20 minutes before slicing.