Knead a homogeneous dough from the flour, butter, egg, salt and water. Let it rest a little and then roll it out. Cut out with suitable round cutters and place in the greased tartlet molds.
Spread the cream cheese on top and top with trout fillet, spinach and tomato. Sprinkle some mozzarella on top. You can also sprinkle salt, pepper, paprika powder or herbs on top to flavor it.
Then bake for about 13-18 minutes in a preheated oven at 180 ° C.