Spread the crème frâiche over the dough. Drain the tomatoes and cut into strips, slice the onion, spread on top of the dough, top with grated cheese, season. Starting from one of the long edges, roll the pastry up tightly to the centre then repeat from the other side, cut into slices approx. 2 cm thick, place on baking trays lined with baking paper.
Bake for approx. 25 mins. in the centre of a fan/convection oven preheated to 180°C.
Slice the radishes and mix them with the lettuce. Combine the mustard, vinegar and oil, season and toss with the salad. Arrange the salad and the warm palmiers on plates.