There’s something incredibly comforting about the rich, silky richness you get in this Creamy Caramelized Onion Pasta Recipe. The slow-sweetened onions and the luscious cashew cream come together in perfect harmony—a treat that’s surprisingly simple but feels so luxurious every time I make it.

A stainless steel pan filled with creamy white sauce coating light yellow fettuccine pasta, with some sauce slightly browned in spots. A woman's hand holds the pan handle at the bottom center, while the other woman's hand stirs the pasta with a wooden spatula on the right side, which has white sauce on its flat side. The pan sits on a sleek gray stove set on a white marbled surface. photo taken with an iphone --ar 2:3 --v 7

Jump to:

Why You'll Love This Recipe
Ingredients & Why They Work
Make It Your Way
Step-by-Step: How I Make Creamy Caramelized Onion Pasta Recipe
Top Tip
How to Serve Creamy Caramelized Onion Pasta Recipe
Make Ahead and Storage
Frequently Asked Questions:
Final Thoughts
Creamy Caramelized Onion Pasta Recipe

Why You'll Love This Recipe

I’m genuinely excited to share this Creamy Caramelized Onion Pasta Recipe with you because it’s one of those dishes that feels like a warm hug after a busy day. It’s not just about the smooth texture or the sweet depth of the onions—it’s about how accessible it is, even on a weeknight!

Deeply flavorful onions: The caramelization process brings out a sweet, rich flavor that’s hard to beat in a simple pasta.
Cashew cream magic: This plant-based sauce is silky and satisfying, perfect for anyone looking to skip dairy without losing creaminess.
Easy to make: With just a few basic ingredients, you end up with a meal that looks impressive but comes together quickly.
Customizable comfort food: You can tweak this recipe easily to fit your taste and pantry, making it a versatile weeknight winner.

Ingredients & Why They Work

Each ingredient in this Creamy Caramelized Onion Pasta Recipe plays a key role. The caramelized onions give sweetness and depth, while the cashew cream adds that dreamy texture and subtle tang. Picking quality, fresh components makes all the difference here.

Flat lay of two large golden-yellow onions sliced thinly next to a small white ceramic bowl of golden oil, a small white ceramic bowl with creamy pale-yellow butter, a small white ceramic bowl filled with fine white salt, a small white ceramic bowl with light brown sugar, a neat nest of uncooked dry fettuccine pasta strands pale ivory in color, a small white ceramic bowl holding soaked raw cashews creamy off-white and plump, a small white ceramic bowl containing clear water, a small white ceramic bowl with bright translucent white vinegar, and a small white ceramic bowl with flaky pale yellow nutritional yeast flakes, all arranged with perfect symmetry and realistic proportions on a clean white marble surface, soft natural light, photo taken with an iPhone, professional food photography style, fresh ingredients, white ceramic bowls, no bottles, no duplicates, no utensils, no packaging --ar 2:3 --v 7 --p m7354615311229779997

Onions: Using large, fresh onions ensures plenty of sweetness when caramelized. Thin, even slicing is essential for that perfect golden brown.
Oil and butter: A combo of both gives great flavor and helps the onions brown without drying out.
Sugar: Just a little to speed up and enhance the caramelization process.
Dry fettuccine pasta: The wide noodles hold onto the creamy sauce beautifully, making every bite luscious.
Raw cashews: Soaked overnight, they blend into a smooth, dairy-free cream that’s rich and silky.
White vinegar: Adds a gentle tang to balance the sweetness.
Nutritional yeast: Provides a subtle cheesy flavor without dairy.
Salt: Enhances all the natural flavors, ensuring the dish isn’t one-dimensional.

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Note: You'll find the complete list of ingredients, along with their exact measurements, in the printable recipe card at the bottom of this post.

Make It Your Way

One of my favorite things about this Creamy Caramelized Onion Pasta Recipe is how easy it is to tweak. I often swap out fresh herbs based on what’s in my garden or pantry, and sometimes I like to add a pinch of chili flakes for a little unexpected heat.

Variation: Adding sautéed mushrooms or spinach is a personal go-to when I want a bit more veggie power without complicating the steps.
Vegan/Gluten-Free Options: Use gluten-free pasta and keep everything plant-based with the cashew cream—you’ll lose nothing in flavor or texture.
Make it richer: Stir in a handful of toasted pine nuts or a sprinkle of vegan parmesan before serving for an extra indulgent touch.

Step-by-Step: How I Make Creamy Caramelized Onion Pasta Recipe

A round white plate holds a nest of flat, wide pasta noodles coated in a creamy white sauce with visible black pepper flakes. Scattered on top are thin, golden brown caramelized onion strips adding texture and color contrast. Fresh green basil leaves are placed on the pasta and around the dish for a pop of color. A silver fork rests on the left side of the plate, partly under the pasta. The plate sits on a white marbled surface with some green basil leaves and a light gray cloth napkin nearby. Photo taken with an iphone --ar 2:3 --v 7

Step 1: Perfectly Slice Your Onions

Start off by peeling two large onions, then slicing them into ⅛-inch thick slices. I find using a sharp knife or a mandoline slicer helps get those even cuts, which means the onions caramelize uniformly and cook without any bits burning or staying tough.

Step 2: Sauté to Golden Perfection

Heat a combo of a tablespoon of oil and butter in a large skillet over medium heat. Once the butter melts, toss in the onions with a pinch of salt, and cook for 5-6 minutes, stirring regularly. You'll notice the onions start to turn a light golden; this is your signal to move to the next step without rushing.

Step 3: Season and Slowly Caramelize

Now add ¼ teaspoon of salt and a teaspoon of sugar. This combo helps speed up caramelization and deepens flavor. Let the onions cook for another 25-30 minutes on medium-low, stirring every few minutes. I've learned that patience really pays off here—don't stir too often, allowing the onions to stick slightly helps develop that gorgeous brown color.

Step 4: Deglaze to Capture Every Bit of Flavor

Once the onions are deeply caramelized, add two tablespoons of water to the skillet to deglaze—scraping up all the bits stuck to the pan. These bits hold incredible flavor, so don’t skip this step. Then, remove the pan from heat and set aside the onions.

Step 5: Blend the Cashew Cream

Drain your soaked cashews and toss them in a blender with half a cup of water, a teaspoon of white vinegar, ¼ teaspoon of salt, and a tablespoon of nutritional yeast. Blend until completely smooth—this sauce is the creamy superstar of the dish and balances those sweet onions perfectly.

Step 6: Cook Pasta & Combine

Cook your fettuccine in salted boiling water until just al dente—remember it’ll cook more in the sauce. Drain, then return the pasta to the skillet with the caramelized onions. Pour in the cashew cream and toss everything together over medium heat for 3-5 minutes, stirring well. If it feels too thick, a splash of pasta water helps loosen the sauce nicely.

Step 7: Final Touches & Serve

Give it a taste and adjust the salt as needed. I like adding fresh parsley or basil for color and that fresh herbal pop. A sprinkle of cracked black pepper finishes it perfectly. Serve immediately—the creamy texture is at its best right away.

Top Tip

From countless times making this Creamy Caramelized Onion Pasta Recipe, I’ve realized a few simple tricks can make the huge difference between “just good” and “wow, that’s amazing.” Here’s what I’ve learned to share with you.

Slow & steady caramelizing: Patience and medium-low heat prevent burning and bring out the natural sugars beautifully.
Don’t over-stir onions: Letting them rest and stick just a bit builds that rich caramel flavor you’re after.
Use reserved pasta water: The starches help the sauce cling better and keep the crema silky without watering it down.
Blend the cashew cream well: For the silkiest sauce, make sure the cashew mixture is completely smooth with no graininess.

How to Serve Creamy Caramelized Onion Pasta Recipe

Caramelized Onion Pasta - Serving Suggestion

Garnishes

I often sprinkle chopped fresh parsley or basil right before serving—it brightens the dish and adds a fresh contrast to the sweet, creamy sauce. Sometimes, a little sprinkle of toasted pine nuts adds a lovely texture and nutty flavor I can’t resist.

Side Dishes

I like pairing this pasta with a crisp green salad dressed simply with lemon and olive oil, or some roasted asparagus or broccoli on the side. The freshness and crunch balance the creamy pasta perfectly and keep things vibrant.

Creative Ways to Present

For special occasions, I serve this pasta in beautiful shallow bowls with a drizzle of extra virgin olive oil around the edges and a few torn basil leaves. Adding edible flowers or microgreens on top makes it feel extra fancy without extra effort.

Make Ahead and Storage

Storing Leftovers

I store leftovers in an airtight container in the fridge and make sure to eat within 2 days for the best texture and taste. The cream thickens a bit overnight, so I usually add a splash of water or broth when reheating to bring it back to life.

Freezing

I don’t usually freeze this pasta because the cashew cream changes texture after freezing, becoming a little grainy. That said, if you have to, freeze portions separately from any fresh garnishes and thaw slowly in the fridge overnight.

Reheating

I reheat leftovers gently on the stovetop over low heat, stirring frequently. Adding a bit of reserved pasta water or broth helps the sauce loosen up and keeps the pasta from drying out or sticking to the pan.

Frequently Asked Questions:

Can I use other types of pasta in this recipe?

Absolutely! While fettuccine is perfect because of its wide shape that holds the creamy sauce well, you can use penne, rigatoni, or even spaghetti. Just adjust cooking times accordingly.

How long does the caramelization of onions take?

It usually takes about 30-35 minutes total over medium-low heat to get deep, rich caramelized onions. Rushing this step can result in burnt or unevenly cooked onions.

Can I make the cashew cream ahead of time?

Yes! The cashew cream can be made a day or two in advance and stored in the fridge in an airtight container. Give it a quick stir or blend before using to refresh the texture.

Is this pasta suitable for vegans and those with dairy allergies?

Definitely! This recipe uses cashew cream instead of dairy, making it a wonderful vegan and dairy-free option, without sacrificing creaminess or flavor.

Final Thoughts

This Creamy Caramelized Onion Pasta Recipe holds a special place in my kitchen — it’s proof that a few simple, thoughtfully cooked ingredients can produce a dish that feels both indulgent and nourishing. I hope you’ll give it a try and discover your own favorite tweaks and moments of joy while cooking it. Share it with people you care about over a cozy meal, and enjoy every creamy, caramelized bite.