5small plums,halved, pitted and sliced into 1/4 inch slices
Preheat the oven to 375 F, and line a baking sheet with parchment paper.
Prepare 1/2 the recipe for all-butter perfect pie dough. Roll the dough out to about 12 inches in diameter. If you like, trim the edges to make it a perfect circle. Place the dough on the baking sheet, and sprinkle the dough with the 2 tablespoons flour.
Arrange the plum slices in an overlapping pattern on the dough, making sure to leave a 1 1/2 inch border of dough all the way around.
Sprinkle 1 1/2 tablespoons sugar, cinnamon and cardamom over the plums, and place the cubes of butter over the plums.
Fold the edges of the dough up, crimping it to keep it in place. Brush the edge of the dough with the beaten egg, and sprinkle with the remaining 1/2 tablespoon sugar.
Bake the galette for about 40-45 minutes, until the crust is crisp and golden brown, and the plum juices are bubbling. Cool for about 30 minutes, and serve warm or at room temperature.