Toast the slices of bread in the toaster or oven (at 200°C) until crispy. Allow to cool. Cube the Gruyère AOP for all fillings. The mustard fruits and dried tomatoes should be coarsely diced.
Using a food chopper or handheld blender, combine ingredients for each filling and season spicily. Spread half of the slices of bread with the fillings, and cover with the remaining slices.