Start with blind baking the puff pastry.
Roll out the puff pastry (I used a shop bought one) onto the baking parchment and fit it into a round baking tray of 26cm in diameter. There should be some extra pastry around the margins of the tray that is best to fold gently, creating a nice little edge.
Prick the pastry with a fork and bake in the preheated oven at 180 C (temperature for a non fan assisted oven, otherwise set the temperature to 170 C) for around 15 minutes. The pastry should become light golden in colour.
Set aside and wait until it cools down.
Once the pastry has cooled down, slice the marzipan and lay its slices on the pastry case, spreading them evenly and covering the whole surface.
Pluck the leaves from a few thyme sprigs and scatter them on top of the marzipan.
Now tightly arrange the plum pieces starting with the outer circle pressing the plums into the edges.
Brush the plum pieces all over with the jam. In case your jam is very thick, heat it up with a dash of water. You can scatter more thyme leaves if you wish.
Dust the tart with the sugar and bake in a preheated oven at 180 C for 35-40 minutes until the pastry becomes golden in colour. Plums should be soft but still holding their shape.
The plum and marzipan tart is best served still warm, with a dollop of crème fraîche or vanilla ice cream if you would like to turn it into a more indulgent pudding.