Once the puff pastry sheets are defrosted lay them out on a flour dusted surface and line them up so they make a square, overlapping each other a little bit. Ofcourse if you can find a whole piece of puff pastry that will work easier but here we can only find the ones that are little squares of 10 by 10 cm.
Line your rectangular tart tin and prick the bottom with a fork to prevent from puffing.
Line your tin with baking paper and use baking weights or dried legumes for blind baking the pastry for about 15 minutes. Remove from the oven, remove the weights and brush lightly with eggwash and place back in the oven for about 10 minutes till lightly golden.
Remove from the oven.
In the meantime put the roasted marzipan in a bowl and whip it a bit with the double cream until it becomes a bit smoother to handle.
Put the marzipan as a layer on top of you puff pastry (be careful not to break the pastry) and cut your plums into slices.
Line the slices up on the marzipan and drizzle with honey. Pop back in the oven and bake for another 30 minutes or until the plums are soft and the pastry golden. Sprinkle with pistachio nuts and enjoy.