Start by dumping the ricotta cheese, milk, and all seasonings into a large bowl and stir.
Add the spinach and the Italian blend cheese, mix again. Cover and set in the fridge while you cook the noodles. While the noodles cook, I slice and saute the mushrooms and onion in 2 tbsp of butter and salt, pepper and garlic until very soft.
After the noodles are al dente, drain them and toss with the olive oil to prevent them sticking to each other.While the noodles cook, add the seasonings and tomatoes to the sauce and stir.
1 at a time, rip or cut 1 side of each manicotti noodle to open it flat. Drop a large spoonful of the mix and roll it back up.
Place them into a glass baking dish(13x9) with a couple spoonfuls of sauce on the bottom. make sure the cut side of the noodle is on the bottom or they'll open.
After all have been made, put a spoonful of sauce on each roll and cover the top with the rest of the Italian blend cheese.
Bake covered on 350 degrees for 20 minutes, then remove foil and cook for another 10-20 minutes or until the pan is bubbly and the cheese starts to brown.