Zucchini and Mushroom Vegetarian Lasagna

Preparation time:  15 minutes
Cooking time:  20 minutes
Baking time:  30 minutes
Makes 12 servings

4 large unpeeled zucchini
1 lb (500g) fresh mushrooms, such as button, brown or shiitake
3 tsp butter
4 crushed garlic cloves
700 ml jar spaghetti sauce
5 1/2 oz can tomato paste
1/2 tsp Italian seasoning
8 oz mozzarella or provolone cheese, grated
475 g container ricotta cheese, well drained
2 eggs
1/4 cup all purpose flour

1. Preheat oven to 350F.  Cut unpeeled zucchini, lengthwise,, into 1/4 inch thick slices.  Take 8 outside slices (the ones that are primarily peel) and finely chop.  Slice mushrooms
2. Melt 1 tsp butter in a large wide saucepan.  Add garlic and chopped zucchini.  Saute over medium heat for 2 minutes.  Remove to paper towels to drain.  Add remaining butter to pan along with mushrooms and saute for 5 minutes.  Drain off all liquid.
3. Add spaghetti sauce, tomato paste, Italian seasoning and cooked zucchini to mushrooms and bring to a boil.  Reduce heat to low and simmer, uncovered, stirring often for 10 minutes.  Stir in half of grated cheese.  Remove pan from heat.  Cover and set aside.
4. Place ricotta, eggs and flour in a food processor.  Whirl, using an on-and-off motion, until smooth.  Or beat with a spoon until smooth.
5. Cover bottom of a 9 x 13 inch baking dish with some of large zucchini slices.  Spread with half of ricotta mixture.  Top with half of tomato sauce.  Repeat layers and sprinkle remaining grated cheese overtop.
6. Bake in centre of oven for 30 to 40 minutes or until hot in centre.  If making ahead, cover and refrigerate for up to 12 hours.  Bring to room temperature before baking.