Thanksgiving for Vegetarian (1) ~~~Lasagne

Personally, I really like Lasagne so I made it freaquently. This year, my friend asked me to make one because she just became vegetarian few months ago. She wants to learn how to make Vegetarian Thanksgiving dinner.
Here is the recipe.

Yield	8 servings
Time	1 hour 15 minutes
Tools	saucepan ladle 9x13-in or other large baking dish
Ingredients	1 pound dry lasagne noodles 2-3 c Italian tomato paste 2 small or one large zucchini, grated ½-1 pound ricotta cheese 3 large bunches spinach, washed and stemmed 1 pound mozzarella cheese, grated or thinly sliced ½ pound provolone, grated or thinly sliced (optional)
Directions	Bring the tomato sauce to a boil, stir in the zucchini, and cook for about 5 minutes. Ladle a bit of sauce into the baking dish and spread it around so that the bottom of the dish is lightly coated. Preheat oven to 350. Place lasagne noodles in the pan to form a single layer. If necessary, break noodles to fill gaps. Spread 1/3 of the ricotta cheese on the noodles, then lay out 1/3 of the spinach on top of that. Sprinkle or place 1/3 of the cheese, then cover with tomato sauce. Repeat twice, using 1/3 of ingredients for each layer, saving a sprinkle of cheese to garnish the top. Bake for about 1 hour, until sauce is bubbly and cheese is melted. Let cool slightly and serve.
Notes	You don't actually need to cook the lasagne noodles ahead of time, as long as they are surrounded by plenty of sauce. The vague amounts of sauce and cheese are deliberate - personally, I like tons of cheese and sauce in my lasagne, but others think it's excessive and prefer more vegetables.