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Epicurious

Caramelized Onion Pasta

By Samantha Seneviratne

4.4

(63)

A speckled white plate with caramelized onion pasta topped with shredded Parmesan cheese.
Photo by Chelsea Kyle, Food Styling by Kate Buckens

All you need for this caramelized onion pasta recipe is a bag of onions, a few cloves of garlic, some dried pasta, and a wedge of cheese. Slowly cooking the sliced onions in butter and olive oil coaxes out their natural sugars, turning them deeply golden, sweet, and almost jammy. Pasta water and finely grated Parmesan do double duty here, adding seasoning and structure as they emulsify into a silky cream-free sauce. Finished with a squeeze of lemon and fresh parsley, this easy vegetarian pasta is proof that a luxurious dinner can come from the most basic pantry ingredients.

Tips and FAQs for the best caramelized onion pasta

  • How long does it take to caramelize onions?
    True caramelized onions take at least 30 minutes over medium heat. Stir occasionally and resist the urge to rush—low, steady heat is key to developing deep flavor without burning.
  • What type of onions work best?
    Sweet onions (Vidalia, Maui, Walla Walla) or yellow onions are the best for caramelized onion pasta because they soften evenly and develop a balanced sweetness. White onions and red onions will work in a pinch, but their flavor will be sharper.
  • What’s the best pasta shape for this recipe?
    Long strands like linguine, spaghetti, or fettuccine work best, as they hold onto the silky onion-Parmesan sauce. More about pairing pasta shape to sauce this way →
  • How can I customize this dish?
    Add red pepper flakes for heat, thyme or sage for earthiness, or crispy breadcrumbs for texture. Toss in some sautéed mushrooms or, for protein, top with a poached egg.
  • Why reserve so much pasta water?
    Having extra pasta water lets you loosen the sauce gradually and achieve a glossy consistency without breaking the creamy (but cream-less) emulsion. You may not need all of it, but as the saying goes, it’s better to have too much than not enough.

Recipe information

  • Total Time

    1 hour

  • Yield

    2–4 servings

Ingredients

2 Tbsp. extra-virgin olive oil
2 Tbsp. unsalted butter
2 lb. sweet or yellow onions (about 4 large), thinly sliced
1 1/2 tsp. kosher salt, plus more
4 garlic cloves, finely chopped
8 oz. linguine or other long strand pasta
4 oz. Parmesan, finely grated (about 2 cups), plus more for serving
½ lemon
½ cup finely chopped parsley

Preparation

  1. Step 1

    Heat 2 Tbsp. extra-virgin olive oil and 2 Tbsp. unsalted butter in a medium Dutch oven or other heavy pot over medium until butter is melted. Add 2 lb. sweet or yellow onions (about 4 large), thinly sliced, a large pinch of kosher salt, and a large pinch of freshly ground black pepper; cook, stirring occasionally, until onions are very tender and deep golden brown, about 30 minutes. Add 4 garlic cloves, finely chopped, and cook, stirring, until fragrant, about 1 minute.

    A person stirring a pot of deeply browned caramelized onions.

    Cook the onions until they are jammy and golden, as seen here; don’t rush it.

    Photo by Chelsea Kyle, Food Styling by Kate Buckens

    Step 2

    Meanwhile, cook 8 oz. linguine or other long strand pasta in a large pot of boiling salted water, stirring occasionally, until very al dente, about 2 minutes less than package directions. Drain, reserving 1½ cups pasta cooking liquid.

    Step 3

    Add pasta and 1 cup pasta cooking liquid to onion mixture and stir to combine. Add a small handful from 4 oz. Parmesan, finely grated (about 2 cups), and stir until melted. Repeat with remaining cheese, adding a handful at a time and adding more pasta cooking liquid as needed until a glossy sauce forms and coats pasta. Squeeze in juice from ½ lemon to taste and stir in ½ cup finely chopped parsley. Taste and season with more pepper if needed.

    Step 4

    Divide pasta among shallow bowls and top with Parmesan and more pepper.

    Do Ahead: Onion and garlic mixture can be made 5 days ahead. Cover and refrigerate or freeze for up to 3 months.

    Editor’s note: This caramelized onion pasta recipe was first printed in April 2019; it has been edited for style. Head this way for more of our favorite pasta dinners →

TagsDinnerPastaLinguineOnionRoot VegetableVegetableParmesanCheeseDairyMainNut FreeVegetarianEasyEpicuriousMake Ahead

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