Roll out the finished tarte flambée dough on a baking tray. Stir the sour cream until creamy, season with salt and pepper and distribute evenly on the tarte flambée batter, avoiding the edges.
Slice the pre-cooked beetroot and spread on the sour cream. Then cut the goat cheese into slices, clean and chop the spring onions and distribute both on the dough.
Put the topped dough in the oven and bake for about 20 minutes until the edges are crispy brown.