There’s something so comforting about pasta bathed in a velvety sauce, and this Creamy Caramelized Onion Pasta Recipe hits that note perfectly. The sweet depth from caramelized onions combined with a luscious cashew cream is just downright dreamy—and surprisingly easy to pull off at home.

A large silver pan filled with thick, flat noodles covered in creamy white sauce sits on a light gray stove with two buttons and a round knob on the right side. The noodles have some light brown spots, and some creamy sauce is spread unevenly around the pan edges. A woman's hand holds a wooden spatula with white sauce on it, stirring the noodles on the right side of the pan. Another woman's hand holds the pot handle at the bottom. The background is 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 don’t know about you, but I love recipes that feel fancy yet don’t demand hours in the kitchen. This Creamy Caramelized Onion Pasta Recipe fits that bill perfectly. Plus, it’s plant-based, so it’s a fresh twist that everyone—vegans and meat-eaters alike—will appreciate.

Deep, rich flavor: Caramelizing the onions slowly unlocks their natural sweetness and umami, making the sauce irresistibly flavorful.
Simple ingredients: You probably already have most of these in your pantry or fridge, making it super accessible.
Plant-based creaminess: The cashew cream adds a silky texture without the heaviness of dairy, perfect for a lighter but indulgent meal.
Versatile & customizable: Easy to tweak with whatever herbs or toppings you love, and perfect for weekday dinners or impressing guests.

Ingredients & Why They Work

This recipe strikes a great balance between simple staples and those little things that elevate flavor and texture. Caramelized onions bring sweetness and depth, the cashew cream adds a dreamy mouthfeel, and fettuccine holds that sauce beautifully. Here’s why each ingredient matters:

Flat lay of two large whole onions with golden caramelized onion slices beside them, a small white ceramic bowl of golden oil, a small white ceramic bowl containing a pat of creamy butter, a small white ceramic bowl of white granulated sugar, a small white ceramic bowl of fine salt, a nest of dry fettuccine pasta, a small white ceramic bowl filled with raw cashews, a small white ceramic bowl with clear water, a small white ceramic bowl with white vinegar, a small white ceramic bowl of nutritional yeast flakes placed in perfect symmetry 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: The star here! Taking the time to caramelize them patiently means layers of sweetness and complexity.
Oil & butter: A combo lets you cook the onions slowly without burning while adding richness.
Salt and sugar: Salt balances the sweetness, while a little sugar helps kickstart the caramelization.
Fettuccine pasta: Wide noodles that catch the creamy sauce and onion bits wonderfully.
Raw cashews: Soaked overnight, they blend into a smooth, creamy base that replaces dairy.
Water: Keeps the cashew cream smooth, with just enough liquid to coat the pasta.
White vinegar: Adds a subtle tanginess to brighten the cream and cut through the richness.
Nutritional yeast: Brings that cheesy, nutty undertone that rounds out the flavor perfectly.

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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

I love that this recipe is so adaptable! I often adjust the herb garnish based on what’s fresh—sometimes basil, sometimes parsley. You can even swap the fettuccine out for gluten-free pasta or add a handful of sautéed mushrooms or spinach for extra veggies.

Variation: I once folded in some toasted pine nuts and a squeeze of lemon juice at the end for a bright, nutty twist—delicious and unexpected.

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

A white plate holds a nest of creamy white fettuccine pasta coated in a smooth, light sauce speckled with black pepper. The pasta is layered with thin, golden-brown caramelized onion strips scattered on top and around, adding texture and a slight shine. Three fresh green basil leaves are placed carefully on the pasta for color contrast. A silver fork rests on the bottom left edge of the plate. The whole scene sits on a white marbled surface with a beige linen cloth peeking out at the bottom right. photo taken with an iphone --ar 2:3 --v 7

Step 1: Slice Onions Thinly and Evenly

Start by peeling your onions and slicing them into consistent ⅛-inch (about 3 mm) thick slices. This thickness ensures they caramelize evenly without burning or taking forever. I find a sharp knife or a mandoline helps keep things neat and consistent, which really matters for uniform cooking.

Step 2: Slowly Sauté Onions with Oil and Butter

Heat the oil and butter in a large skillet over medium heat. Once the butter melts, add the onions with a pinch of salt to draw out moisture. Cook for about 5-6 minutes, stirring every few minutes, until the onions start turning a light golden shade. Patience is key here—slow heat helps those natural sugars develop beautifully.

Step 3: Season and Caramelize Until Deep Gold

Sprinkle in the rest of the salt and sugar, then lower the heat to medium-low. Let the onions cook gently for another 25-30 minutes, stirring occasionally. This slow caramelization is what gives the dish such rich flavor—watch for a deep golden brown color. If you see them browning too quickly, lower the heat to avoid burning.

Step 4: Deglaze the Pan

Pour 2 tablespoons of water into the skillet and use a spatula to scrape the browned bits off the bottom. This step lifts all the flavor packed on the pan and adds it back into the onions. Then remove the skillet from heat but keep those onions inside.

Step 5: Blend Cashew Cream

Drain your soaked cashews and toss them in a blender along with water, white vinegar, salt, and nutritional yeast. Blend on high for 20-30 seconds until beautifully smooth. This creamy base is what makes the sauce rich but still dairy-free.

Step 6: Cook Pasta Al Dente

Boil salted water and cook your fettuccine until just al dente—remember it’ll keep cooking slightly when combined with the sauce. Drain and transfer the noodles directly into the skillet with the caramelized onions.

Step 7: Toss Pasta with Cashew Cream

Pour the cashew cream over the pasta and onions, then toss gently with tongs or spatulas to coat evenly. Heat over medium for 3-5 minutes, stirring often to let flavors meld. If the sauce seems too thick, add a splash of the reserved pasta water or regular water to loosen it up to your liking.

Step 8: Season and Serve

Give it a final taste and adjust the salt if needed. I love finishing with freshly ground black pepper and a sprinkle of chopped parsley or basil for brightness. Serve warm and enjoy immediately for the best texture and flavor.

Top Tip

From my experience, the magic in this Creamy Caramelized Onion Pasta Recipe truly lies in the caramelization process. Here are some practical tips I’ve learned over time to get that golden, deeply flavorful onion base without any bitterness or burning.

The Patience Principle: Don’t rush the caramelizing; medium-low heat and slow stirring every 3-5 minutes lets the onions develop natural sugars beautifully.
Even Slices Matter: Uneven slices cook unevenly—thin and uniform slices ensure all onions finish caramelizing at roughly the same time.
Use the Deglaze: Don’t skip adding a bit of water to lift those browned bits off the pan—it holds so much flavor!
Reserve Pasta Water: Keep some pasta water aside to adjust your sauce if it gets too thick; its starches help the sauce cling beautifully to the pasta.

How to Serve Creamy Caramelized Onion Pasta Recipe

Caramelized Onion Pasta - Serving Suggestion

Garnishes

I usually top mine with freshly chopped parsley or basil—both add a fresh pop that balances the richness wonderfully. A sprinkle of cracked black pepper and a little extra nutritional yeast or vegan parmesan also make for a lovely finish.

Side Dishes

This pasta pairs beautifully with a crisp mixed greens salad dressed simply with lemon and olive oil. You could also serve it alongside roasted veggies or garlic bread for a heartier meal. Trust me, the contrast between creamy pasta and crunchy greens is a winner every time.

Creative Ways to Present

For special occasions, I like to serve this in individual shallow bowls garnished with microgreens and a drizzle of herb-infused oil. Adding some toasted walnuts or pumpkin seeds on top gives a nice crunch and a touch of elegance.

Make Ahead and Storage

Storing Leftovers

I store leftovers in an airtight container in the fridge and they keep nicely for up to 2 days. The sauce thickens a bit as it cools, so be ready to loosen it up with a splash of water or plant milk when reheating.

Freezing

I haven’t frozen this pasta often because it’s so quick to make fresh, but if you do, freeze it in a sealed container without garnishes. When thawed, the sauce can separate a bit, so just give it a good stir and add a splash of water while reheating.

Reheating

Reheat gently on the stove over low heat, stirring frequently. Add a little reserved pasta water or regular water to thin the sauce if needed—microwaving works too but can dry things out, so watch the time carefully.

Frequently Asked Questions:

Can I use a different type of pasta for this Creamy Caramelized Onion Pasta Recipe?

Absolutely! While fettuccine is great for holding the luscious cashew cream, feel free to use any pasta shape you enjoy—penne, linguine, or even gluten-free options work well. Just cook according to the package instructions and adjust the sauce quantity slightly if needed.

Do I have to soak the cashews overnight?

Soaking cashews overnight makes them super soft and easy to blend into a creamy texture. If you’re short on time, soaking them in very hot water for 1-2 hours can work as a shortcut, but overnight soaking is best for smoothness.

Can I substitute the cashew cream with dairy cream or another alternative?

Yes, if you’re not avoiding dairy, a splash of heavy cream or half-and-half can be used instead of cashew cream. For other plant-based options, blended silken tofu or coconut cream are decent substitutes, though they’ll change the flavor and texture a bit.

How do I prevent the onions from burning during caramelization?

The key is low to medium-low heat and patience. Stir your onions every 3-5 minutes instead of constantly, and watch that the pan doesn’t get too hot. If the onions start browning too quickly, just turn the heat down a notch. Keeping some fat (oil and butter) in the pan helps prevent sticking and burning.

Final Thoughts

This Creamy Caramelized Onion Pasta Recipe has quickly become one of my go-to comfort dishes—not just for its luxurious flavor, but how it feels like a little kitchen hug when I need it most. I hope you’ll give it a try and make it your own. Trust me, once you nail that sweet, caramelized onion base and creamy sauce, this will be a recipe you turn to time and again.