Mix creme fraiche and mustard and season with salt and pepper. Peel labels from the tins, whip tins on the edge of the table and remove the dough. Separate triangles from each other and place each one on a work surface.
Spread each with 1 tablespoon of mustard cream. Place one sausage on each broad end and roll up. Grate cheese and sprinkle on the dough. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 10-15 minutes.
Decorate with cherry tomatoes and flags.