Creamy Spinach and Mushroom White Lasagna

Slice of white sauce spinach lasagna on a spatula coming out of a pan.

5 from 19 votes

Creamy Spinach and Mushroom White Lasagna

Layers upon layers of Italian sausage, spinach, and mushroom lasagna made with the most delicious creamy white ricotta cheese alfredo sauce. This recipe is so versatile and easy to make. I've made this four times this month for parties and potlucks and casserole dish is always empty! A huge crowd pleaser!

Prep Time30

Cook Time1

Total Time1 30

Course: dinner

Cuisine: Italian

Servings: people

Calories: 413kcal

Author: Amanda Mason

Ingredients

Packaged Alfredo White Lasagna

9 lasagna noodles, oven ready or traditional
1 15 ounce package whole milk ricotta
2 10 ounce Buitoni alfredo sauce
3 cups shredded mozzarella cheese, divided
¾ cups Parmesan cheese, divided
2 10 ounce packages frozen chopped spinach, thawed and drained
1 lb Italian sausage, ground
1 lb cremini mushrooms, finely chopped
1 onion, finely chopped
3 cloves garlic, finely chopped
¼ teaspoon Italian seasoning
½ teaspoon dried oregano
1 teaspoon dried basil
fresh parsley, to taste
salt and pepper, to taste

How to Make Homemade Alfredo Sauce

¼ cup unsalted butter
1 onion, diced
3 garlic cloves
¼ cup all-purpose flour
3 cups milk, at room temperature
1 teaspoon dried basil
½ teaspoon dried oregano
¼ teaspoon Italian seasoning
⅛ teaspoon nutmeg
salt and pepper, to taste

Instructions

Packaged Alfredo White Lasagna

Brown the Italian sausage in a large skillet. When done, drain and transfer the sausage to a cutting board. With a sharp knife, finely chop the sausage and then set aside.
Using a large saucepan, open 2 tubs of Buitoni alfredo sauce and pour into the pan. Simmer on medium-low heat until warm.
While the alfredo is warming, finely chop the mushrooms, onion, and fresh garlic.
In a large pan, saute on medium heat for 5-6 minutes.
Add in the chopped Italian Sausage and saute for another 5-6 minutes until the mushrooms and onions are tender. Set aside.
Now it's time to prepare the ricotta cheese. Put the ricotta cheese, oregano, basil, and Italian seasoning in a medium bowl and mix well with an electric mixer on low speed, about 30 seconds. Set aside.
It's now time to start the layering process.
First, add a ½ cup of the warmed alfredo sauce to the bottom of a 13x9 oven safe pyrex dish. Expert Tips: This will ensure the noodles don't stick to the bottom of the dish.
Then, place 3-4 lasagna noodles on top of the sauce. From there, add half of the ricotta cheese on top of the lasagna noodles and spread evenly using a basting brush.
Layer half of the spinach on top of the ricotta cheese and spread evenly.
Next, add half the sausage, onion, mushroom, and garlic mixture on top.
Add 1 ½ cups of shredded mozzarella cheese and half the Parmesan cheese and spread out evenly.
Layer on 3-4 more lasagna noodles on top of the mozzarella cheese. Now, pour on half the alfredo sauce.
Repeat the layering by following steps 6-11 again.
Once the lasagna has been put together, cover with aluminum foil and bake on 350°F for 1 hour.
Once done, remove the aluminum foil and let it rest for 10 minutes before slicing. Top with fresh parsley and serve.

Homemade Alfredo Sauce

Melt the butter in the saucepan over medium heat. Add the chopped garlic and onion and saute until tender, about 3-4 minutes.
Whisk in the flour until lightly browned, about 1-2 minutes.
While whisking continuously, slowly pour in the milk and cook until slightly thickened, about 2-3 minutes.
Stir in the basil, oregano, Italian seasoning, and nutmeg until fragrant. Add in salt and pepper to taste.
Reduce the heat to low and continue to simmer for 7-10 minutes until it starts to thicken.

Notes

While you can use oven ready lasagne noodles, my preference is to use traditional lasagna noodles for this recipe. I like boiling them to an al dente texture and letting the sauce and other ingredients blend in while everything is cooking in the oven. If you're gluten free, you can use a gluten free lasagna noodle for this recipe.
It's super important to finely chop the ground Italian sausage and mushrooms. It changes the taste and consistency of the dish if the sausage and mushrooms are too chunky.
When spreading the ricotta cheese, use a basting brush. You can even dip it in the alfredo sauce to help spread it around. This method will make your life a whole lot easier because ricotta is hard to spread.
This lasagna recipe is freezer friendly! All you need to do is complete steps 1-11 using a 9x13 freezable container. Wrap the pan in aluminum foil and freeze for up to 3 months. When you're ready to cook the frozen lasagna, place it in the refrigerator and let is thaw completely. Once thawed, cook on 350°F for 1 hour until heated all the way through.

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