Clean, wash and drain the spinach well. Heat butter in a pan. Sauté the spinach for 2-3 minutes until the liquid has evaporated. Season spinach with salt, pepper and nutmeg and remove from the heat.
Wash and halve the tomatoes and cut them into thin slices. Wash the chicken filet, dab dry and cut into slices. Heat oil in a pan. Brown the meat in it and season with salt and pepper.
Add meat to the spinach. Grate cheese. Unroll the dough and place on a baking tray lined with baking paper. Divide the pizza dough lengthwise into thirds, then halve it crosswise. Cut each rectangle in half again diagonally.
Pull pieces apart. Spread the pizza pieces with tomato sauce and cover with tomato slices. Add spinach and fillet slices and sprinkle with cheese. Bake the pizza corners in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 15-18 minutes.