Preheat the oven to 350°F (180°C). Roll out the pie crust and place it in a tart pan. Prick the bottom with a fork.

Place a sheet of parchment paper and pie weights on top, then bake for 10 minutes to partially cook the crust.

Meanwhile, cut the plums in half, then slice each half into about 3 wedges. Place them in a shallow bowl, sprinkle with sugar, and toss to coat.

In a mixing bowl, combine the eggs, sugar, sour cream or crème fraîche, and almond flour. Mix well, then pour the mixture into the partially baked tart crust.

Arrange the sugared plum slices in a circular pattern over the almond cream. If there is any juice left, drizzle it over the tart. Sprinkle with a few sliced almonds.

Bake for 30 minutes at 350°F (180°C), until the tart is golden brown.

Serve warm or cold.