In a large, deep pan over medium heat, sauté the onion and garlic in the butter until the onion is translucent, 5 to 7 minutes. Add the flour and stir well for one minute to make a roux.

Add the tomato paste, salt, oregano, marjoram, and thyme and mix well. Add the crushed tomatoes and stir to combine. Add the water, cover, and simmer for one hour.

Add a little of the hot liquid to the egg yolk, then whisk into the soup.

In a deep pan or casserole dish (or individual dishes if you wish), layer half of the bread and sprinkle with 1/3 of the cheese. Add the remaining bread and sprinkle with 1/3 of the cheese. Add the soup and top with remaining 1/3 cheese.

Bake 45 minutes at 325 degrees or until bubbly. Cheese should be nicely browned.