Caramelized Onion Pasta is my go-to “what’s-for-dinner” pasta when I want something warm, comforting, and low-lift (meaning, I ran out of time and need dinner fast). It’s made with simple pantry ingredients, but the way it comes together makes one of the best red pasta sauces you’ll ever have.

The key here is the technique: you’ll slowly caramelize onions, stir in tomato paste until it’s a deep brick red (yes, you have to cook tomato paste in olive oil to maximize its flavor and cut the bitterness), and bring it all together with starchy pasta water to create a glossy, silky sauce that clings to every strand. Fresh garlic and optional chilis add incredible flavor. (I love Calabrian chilis, but just a touch because they’re hot! Chili flakes work, too.)

This isn’t a traditional Italian dish. It’s more Italian-inspired. A version of it went viral after appearing in The New York Times: Alison Roman’s shallot pasta (aka #ThePasta) became an instant hit. I’ve tweaked it over the years based on what I have on hand in my pantry, and it’s a hit every time.

No fancy ingredients, just smart technique and a few finishing touches turn pantry basics into a truly special pasta. That’s exactly the kind of recipe I love to keep in rotation.

In short: slowly cook 1 large sliced yellow onion in 1/4 cup of olive oil for 15 minutes, add 3 cloves of sliced garlic for 5 more, then stir in 1/4 cup of tomato paste until it turns brick red. Toss it with 16 ounces of bucatini and about 1 cup of starchy pasta water, and dinner for 4 is ready in about 35 minutes.

What You’ll Love About Caramelized Onion Pasta

• Pantry-friendly & Inexpensive: This easy pasta recipe is made with inexpensive ingredients you may already have on hand (aka a great pantry pasta!)
• Rich, slow-cooked flavor: Caramelized onions and tomato paste build a deep, savory base, which gives this pasta a surprisingly deep flavor with minimal ingredients and effort.
• Easy to make: It takes just 2 pots and about 35 minutes from start to finish, making it perfect for those busy weeknight meals.
• Customizable: Add herbs, extra chili, anchovies if you fancy, or a protein of your choice to make it a complete meal.

Ingredients For Caramelized Onion Pasta

• Olive oil: Acts as the base for sautéing and brings a rich, fruity depth to the sauce. Use a good quality extra virgin olive oil, if you can.
• Yellow onion: Slowly caramelized to bring out its natural sweetness and create the backbone of the sauce. For an alternative, you can use shallots. This will offer a slightly milder, more delicate flavor if you prefer.
• Garlic cloves: Adds warmth and aromatic depth. Thin slices melt right into the sauce for a mellow garlic presence.
• Tomato paste: Rich in umami and natural sweetness. It slow-cooks in the olive oil to create a velvety, tomato-forward sauce with just the right amount of tang.
• Calabrian chilis: For a kick of heat. Calabrian chilis offer a fruity, smoky spice that balances beautifully with the sweet onions. You can swap in red pepper flakes if needed.
• Kosher salt and freshly ground black pepper: Essential for building flavor throughout the cooking process.
• Bucatini or any pasta you love: Bucatini (a thick, long-cut pasta with a tiny hole running through the middle) is great because it’s perfect for soaking up that luscious sauce. But truly, any pasta works here, so use what you have on hand.
• Reserved pasta water: Don’t skip this! The starchy pasta water helps the sauce emulsify, turning it glossy and clingy in the best way.
• Freshly grated Parmesan or Pecorino: Adds a salty, savory finish. Both cheeses melt beautifully over the hot pasta.
• Fresh or dried oregano: For a pop of color and a final layer of flavor. Oregano adds a nice earthy note.

(See full list of ingredients and amounts in the printable recipe card below.)

How to Make Caramelized Onion Pasta

1. Caramelize the onions: In a large skillet or Dutch oven, heat olive oil over medium. Add sliced onion with a pinch of salt and pepper. Cook 15 minutes, stirring occasionally, until soft and golden. (Meanwhile, bring a large pot of salted water to a boil.)
2. Add the garlic: Stir in sliced garlic and cook for another 5 minutes, until softened and fragrant. Drop the pasta into the boiling water now.
3. Stir in tomato paste: Add tomato paste with another pinch of salt and pepper. Stir continuously for 3 minutes, until the paste darkens to a brick red color and caramelizes slightly.
4. Add the chili: Stir in Calabrian chilis or red pepper flakes to taste. Cook 1 minute to bloom the flavors.
5. Cook the pasta: Boil pasta until just shy of al dente. Reserve 1 cup of the starchy pasta water before draining.
6. Bring it all together: Add the drained pasta directly to the sauce along with ½ cup of pasta water. Toss gently, letting it simmer for 3 minutes. Add more water as needed until the sauce is glossy and clings beautifully.
7. Serve and garnish: Top with freshly grated Parmesan or Pecorino, a sprinkle of oregano, and a final pinch of flaky sea salt. Serve hot and enjoy immediately.

Tips for Caramelized Onion Pasta:

• Save the pasta water! This sauce relies on about 1 cup of pasta water, so if you drain your pasta water, be sure to save a few cups (it’s better to have more than not enough).
• Onions vs Shallots: Any onion or shallot works here. One of the best parts about caramelized onion pasta is that you can use what you have. I’ve used 1 small yellow onion with a few shallots and it was awesome. Any onion can work here, and I like the mild sweetness of a yellow onion if I have one. The measurements are also flexible. One large onion or 2 small-to-medium onions is what you’re looking for.
• Optional add-ins: The original NYT recipe calls for anchovies, but I usually don’t use them because my kids don’t like them (yes, they can taste them even though they “melt into the sauce”). If you love anchovies, cook some down in the oil before adding the onions. This sauce is wonderful without them, and it’s one less ingredient to think about.
• Make-ahead sauce option: This sauce is a paste until you add the pasta cooking water to turn it into a luxurious sauce. If you want to make this ahead, make the paste and store it in an airtight container (e.g., a jar with a lid) in the fridge for up to 10 days. Then all you have to do is boil water for the pasta and, in a separate large skillet or Dutch oven, heat the paste over medium heat while the pasta cooks. When the pasta is 1 minute shy of al dente, add 1/2 cup of the pasta water, then the pasta, and toss it together to make a velvety sauce. You’ll probably need more pasta water, about 1 cup depending on the pasta you choose.
• Make it gluten-free: Make it gluten-free by swapping out the pasta for your favorite gluten-free noodles.

Caramelized Onion Pasta FAQs

Does caramelized onion pasta have cream in it?

There’s no cream at all. The silky texture comes from the tomato paste and olive oil coming together with starchy pasta water, which is why saving that water matters so much.

Can I use chili oil instead of Calabrian chilis?

A drizzle of chili oil works great, either stirred into the sauce or spooned over the top at the end. Red pepper flakes are another easy swap. Start small and add more to taste.

Can I add chicken?

Sliced oven-baked chicken breast or shredded rotisserie chicken turns this into a heartier meal. Toss it in with the pasta at the end so it warms through in the sauce.

How long do leftovers last?

Up to 4 days in an airtight container in the fridge. Add a splash of water when you reheat it so the sauce loosens up and turns glossy again.

Looking for another quick pasta night? Try my Quick Pasta alla Vodka or Angel Hair Pasta.

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