Roll out the puff pastry and cut into 12 square pieces. Preheat the oven to 180 degrees and line a baking sheet with parchment paper. Place the puff pastry squares on the prepared tray.
Wash, halve and core the plums. Pour the plum jam into the core hole of the plum halves with a spoon. Place one half of the plum with the filled hole facing down on a square of puff pastry.
Whisk the egg yolks and brush the pastry around the plums. Then sprinkle with a little cinnamon sugar.
Then bake in the oven for about 10-15 minutes. When the squares are golden brown, remove them. Let the puff pastry cool, dust with powdered sugar and serve.
Tip:
For those who prefer something a little sweeter: It also tastes very tasty with peach halves from the tin instead of the plums. Then replace the plum jam with apricot jam