Wash the turkey filet and dab dry. Heat 2 tablespoons of oil in a pan. Brown the meat well all around and fry for another 10 minutes at medium heat. Clean, wash and drain the spinach.
Peel and finely chop the onion. Heat 1 tablespoon of oil in a saucepan. Brown the onion in it, add the spinach and let it fall together. Season with salt and pepper. Take the meat out, let it cool down and cut it into thin slices.
Clean, wash, quarter, seed and cut the tomato into small cubes. Cut mozzarella into slices. Slice bread lengthwise and spread with cream cheese. Drain spinach a little and spread on the breads.
Place the turkey breast on the spinach. Place mozzarella slices on top and sprinkle with the tomato cubes. Bake the bread in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 8 minutes.