1. 1. Preheat your oven to 375°F (190°C).

2. 2. In a food processor, combine the all-purpose flour and salt. Add the chilled butter cubes and pulse until the mixture resembles coarse crumbs.

3. 3. Gradually add the ice water while pulsing, until the dough just begins to come together.

4. 4. Turn the dough out onto a lightly floured surface and gently shape it into a disk. Wrap in plastic wrap and refrigerate for 30 minutes.

5. 5. In a large bowl, toss the sliced plums with the granulated sugar and vanilla extract.

6. 6. Roll out the chilled dough into a 12-inch circle and transfer it to a baking sheet lined with parchment paper.

7. 7. Arrange the plum slices in a circular pattern on the dough, leaving a 2-inch border.

8. 8. In a small bowl, mix the almond flour and heavy cream until a smooth paste forms.

9. 9. Dollop the almond cream mixture over the plums and spread it evenly, leaving a 1-inch border.

10. 10. Fold the dough border over the plums, creating a rustic galette shape.

11. 11. Brush the dough with the beaten egg.

12. 12. Bake the galette for 35-40 minutes, or until the crust is golden brown and the plums are tender.

13. 13. Allow the galette to cool for 15 minutes before slicing and serving.