Sweat the onions with olive oil in a pan and add the garlic. Then add the spinach and fry it until it is cooked.
Spoon the mixture into a bowl before adding the flour, breadcrumbs, cheese, and herbs. Add the egg yolks with the salt and pepper to the bowl and mix everything.
Beat the egg whites until they're stiff. Fold the beaten egg whites into the spinach mix.
Spread the mixture in a greased square-shaped pan. Bake the spinach pastry for 20 minutes at 320°F.
Fry the mushrooms with the carrots and some oil in a pan.
Place the spinach square on a clean dishcloth and spoon the mushroom and carrot mix onto the center. Sprinkle some grated cheese on top. Roll up the spinach square using the dishcloth.
Sprinkle the mozzarella on top and place the spinach roll back in the oven so that the cheese melts into it.
