Spinach & Mushroom Stuffed Shells

I had an open box of large shell pasta that was half gone in the pantry, so I thought I'd add stuffed shells to the menu for this week.  When I was looking at my saved recipes, I came across this one from Two Peas and Their Pod for Spinach Mushroom Cannelloni.  The filling sounded delicious, so I thought I'd use it to stuff my shells.  I had some filling left over, so I spread it on some lasagna noodles and rolled those up, too.  What a delicious dinner.  Joel requested this filling inside of lasagna one day, too.

2 tablespoons Olive Oil
1 Onion, chopped
1 Garlic Clove, minced
3 cups Fresh Spinach
2 cups Mushrooms, sliced
1 1/2 cups Ricotta Cheese
1/2 cup Mozzarella Cheese, shredded
1/4 cup Parmesan Cheese, shredded
1 Egg, beaten
1 teaspoon Dried Basil
1/2 teaspoon Dried Oregano
1/4 teaspoon Black Pepper
1/2 teaspoon Salt

Large Shell Pasta (I used about 12 shells and 6 sheets of lasagna noodles)

Sauce of your choosing (I cheated and used a jarred sauce)

Cook the shells according to package directions.  When the shells are done cooking, drain them and set them aside to cool slightly.  Meanwhile, in a large saucepan, heat the olive oil over medium-high heat.  Add the onion and garlic, cooking until tender, about 5 minutes.  Stir in the spinach and mushrooms and cook until the mushrooms are soft and the spinach is wilted, about 5 minutes.  Remove from the heat.  In a large bowl, stir together the ricotta cheese, mozzarella cheese, and Parmesan cheese.  Add the egg and mix until well combined.  Stir in the spinach mixture and seasonings.  Gently spoon the filling into the cooked shells until all has been used up.  Pour a little sauce on the bottom of a 9x13 baking dish. Place the shells in the dish and cover with more sauce.  Bake at 350 degrees for 30-40 minutes.