Break 3 pasta sheets and arrange them evenly in the cake pan. Spread ½ cup of pasta sauce over it. Spread half of the spinach-mushroom mixture over the sauce. Spread half of the mixed cheese evenly.
We prefer to use low fat ricotta and mozzarella cheese and skip egg. Feel free to use your favorite cheeses, more or less and add egg if you like. Broil the lasagna for a couple of minutes to get crispy top if you like. The lasagna will be delicious either ways!