For the mini cinnamon tarts, defrost the puff pastry sheets. In the meantime, preheat the oven to 180°C degrees.
Grease 12 tartlet tins with softened fat and dust thinly with flour. Beat butter and sugar until thick and fluffy. Gradually beat in the eggs, whipped cream, almonds and cinnamon.
Roll out the puff pastry thinly on a floured surface. Line a ramekin with the pastry and place it on a baking tray. Pour in the cinnamon mixture and bake for about 18 minutes. If desired, serve the mini cinnamon tarts dusted with powdered sugar.