Creamy Mushroom and Spinach Pasta with Caramelized Onions (2024)

This post may contain affiliate links. For more information, please see our affiliate policy.

Creamy mushroom spinach pasta with caramelized onions is smothered in Parmesan cream sauce. This easy meatless dish tastes like the main course from an Italian restaurant.

Caramelized onions add so much needed flavor to this meatless pasta. I use long pasta, such as fettuccine noodles, which work perfectly with the long strands of caramelized onions.

If you enjoy meatless pasta recipes with lots of flavor, be sure to check out this sun-dried tomato and mushroom pasta and vodka tomato sauce pasta.

What makes this mushroom spinach pasta special?

• The recipe uses basic, easy-to-find ingredients. In fact, the recipe uses just a few ingredients. Everything you use in this recipe can be found in most grocery stores.
• Pasta with mushrooms and spinach can be quite bland. Not this one, though! Why? First, caramelized onions add incredible flavor dimension. Second, you smother everything in a cream sauce. This pasta is anything BUT bland.
• I use shiitake mushrooms that provide rich, meaty flavor to the pasta.
• You don't need meat for this meatless pasta dish. To reinforce my point #2, pasta with mushrooms and spinach could be bland and therefore require meat. But because of the cream sauce and the caramelized onions, you will feel that this is a complete meal that doesn't even need meat.

Using shiitake mushrooms in a pasta dish

In this recipe, I use shiitake mushrooms. Why? Because they have a rich, meaty flavor that complements creamy pasta perfectly. Remember my point early on that this recipe doesn't need meat? Well, just try shiitake mushrooms and you'll see why. Shiitake mushrooms provide thick, chewy, yet soft texture and add a "meaty" component to this spinach pasta.

Although I love shiitake mushrooms in this pasta, you, of course, can substitute all kinds of other mushrooms for shiitake. If you can't find shiitake, use portobello mushrooms or cremini mushrooms - both of these will be excellent substitutions for shiitake.

Substitutions

• I use fettuccine noodles (wide long pasta). You can also use spaghetti, linguine, angel hair pasta. I do prefer to use long pasta in this recipe vs. short pasta, such as penne. Long pasta makes a better presentation with caramelized onions, spinach, and mushrooms.
• To make this pasta gluten-free, use gluten-free fettuccine or any other type of long gluten-free pasta. Gluten-free brown rice fettuccine will work great!
• To make the cream sauce I use heavy cream + milk. You can totally substitute half and half for that (in the same amounts).
• Don't have shiitake mushrooms? Use portobello or cremini mushrooms.

To top it all, this spinach and mushroom pasta turned out to be quite versatile, too. You could definitely eat this creamy pasta loaded with vegetables as a stand-alone, meatless dish. It also makes a surprisingly great side dish for a grilled steak, pork or chicken. In fact, this pasta recipe happens to combine all of my 4 favorite sides for steak in one: mushrooms, creamed spinach, caramelized onions, and creamy pasta with cheese.

So, feel free to eat this pasta as a stand-alone meatless dinner or add a piece of grilled steak, pork, or chicken.

How to make Creamy Mushroom Spinach Pasta with Caramelized Onions

Here are some step-by-step photos illustrating how to make this pasta. Scroll all the way down for the complete recipe.

1) First, caramelize onions for 30 minutes to reach a nice deep brown color. (See: how to caramelize onions) Deglaze with a small amount of balsamic vinegar.

2) Next, cook shiitake mushrooms (without stems) in 1 tablespoon of olive oil. You can use any type of mushrooms of small size.

3) Then, add spinach to caramelized onions and mushrooms mixture, stir until spinach wilts.

4) Next, add heavy cream, milk, Parmesan cheese and salt to the vegetable mixture.

5) Add cooked and drained pasta and cook for 5-10 minutes on low heat so that creamy sauce coats pasta and Parmesan cheese melts and coats pasta as well.

Tips for making pasta sauce super creamy

Does your cream sauce clump as you're trying to make it? Or, does the sauce separate in the process? Here is how to avoid and fix all these problems:

• Make sure your pan or skillet is very hot before you add the cream sauce ingredients. In this recipe, this is achieved by caramelizing the onions first, cooking the mushrooms, then wilting the spinach - all in the same skillet. This ensures that the pan is already very well heated.
• Bring heavy cream and milk to a boil just for a second.Immediately, add shredded Parmesan cheese, make sure everything is boiling. Then,immediately reduce everything to simmer. The point in doing all this is again to make sure your cooking pan/skillet is hot enough to handle the sauce. The cheese simply will not melt properly if the ingredients are not hot enough. Bringing everything to a short boil and then reducing heat to simmer (low boiling, but still boiling point) ensures the melting of the cheese instead of clumping.
• Keep stirring the sauce at all times. This ensures again that the sauce is smooth and has a consistent, even texture. Do not continue to boil the cream sauce. Bring everything to simmer immediately after reaching the boiling point as described above.
• If your sauce is too thick after adding the cheese, thin out the sauce by slowly adding milk (or half-and-half) while simmering the sauce. Make sure the sauce continues to simmer and does not come to a standstill, while you add milk to thin it out.

More delicious mushroom pasta recipes

I love combining mushrooms and pasta:

• If you want simplicity and you love garlic and butter, you'll love this super easy meatlessgarlic and mushroom pastasmothered in butter and shredded Parmesan.
• If you want meat, such as chicken, and enjoy the more complex flavor, check out this chicken pesto pasta with mushrooms - it's so creamy and the basil pesto sauce combines beautifully with chicken, pasta, and mushrooms.
• How about homemade vodka sauce with mushrooms? And chicken? Then definitely try one of my all-time favorites: penne pasta in creamy vodka tomato sauce with mushrooms.

This recipe was originally published on January 22, 2013, and republished with updates, cooking tips in June 2018.