Roll out the dough, slide onto two trays along with the baking paper. Season the crème fraîche and spread on top of the dough. Mix the onions and radishes with the oil, spread on top of the dough along with the diced bacon.
Approx. 20 mins. on the bottom shelf of an oven preheated to 240°C. Bake the second tarte flambée in the same way.
Whisk the vinegar and oil, season with salt. Add the radishes, mix, spread on top of the tarte flambées and add the basil.