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caramelized onion pasta recipe featured
Avatar photoJohnson Maya

Easy Caramelized Onion Pasta Recipe

A rich, creamy, and deeply flavorful pasta dish featuring slowly caramelized onions, fresh thyme, and Parmesan. Simple ingredients, gourmet results—perfect for a cozy dinner or elegant gathering.
Prep Time 15 minutes
Cook Time 35 minutes
Total Time 50 minutes
Servings: 4 servings
Course: Main Course
Cuisine: American
Calories: 420
Ingredients Equipment Method Nutrition Notes

Ingredients
  

  • FOR THE MAIN DISH:
  • 2 large yellow onions (about 400g), thinly sliced
  • 4 tablespoons (60g) unsalted butter
  • 2 cloves garlic, minced
  • 1 tablespoon fresh thyme leaves
  • 1 pound (450g) dried fettuccine or pappardelle
  • 1/2 cup (50g) freshly grated Parmesan cheese
  • 1/2 teaspoon flaky sea salt, or to taste
  • 1/4 teaspoon freshly ground black pepper
  • 1/2 cup (120ml) reserved pasta water

Equipment

  • Large skillet
  • Chef's knife
  • Cutting board
  • Large pot
  • Wooden spoon
  • Measuring cups and spoons

Method
 

  1. caramelized onion pasta recipe recipeCard1
  2. Begin by peeling and thinly slicing two large yellow onions into uniform half-moons to ensure even cooking. Keep slices consistent—about 1/8-inch thick—to prevent some pieces from burning while others remain crisp. Rinse and dry your knife and cutting board promptly to avoid lingering onion odor. Store extra onions in a sealed container in the fridge for up to five days.
  3. Melt butter in a large, heavy-bottomed skillet over medium-low heat. Add onions and stir to coat in fat. Cook for 25–30 minutes, stirring occasionally, until they turn deep golden brown. Resist the urge to crank the heat—high heat burns instead of caramelizes, creating acrid flavors. Lower heat ensures even sugar breakdown and Maillard reaction.
  4. While onions caramelize, bring a large pot of salted water to a boil. Add fettuccine and cook for 8–10 minutes, or until just shy of tender. Reserve 1/2 cup of pasta water before draining—it's rich in starch and will help the sauce cling to the noodles.
  5. Once onions are caramelized, add minced garlic and thyme to the skillet. Sauté for 1–2 minutes until fragrant. Slowly pour in reserved pasta water and stir to create a silky sauce. Add Parmesan gradually, whisking continuously to emulsify. Finish with a knob of butter for extra gloss, if desired.
  6. Add drained pasta to the skillet, tossing gently over low heat for 2–3 minutes to fully coat. Season with salt and pepper to taste. Let the dish rest for 2 minutes before serving to let flavors meld.

Nutrition

Calories: 420 | Carbohydrates: 58 | Protein: 12 | Fat: 16 | Fiber: 3 | Sugar: 6

Notes

STORAGE: Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently over low heat with a splash of water or broth to restore moisture. Do not freeze as the texture will change.
MAKE AHEAD: Caramelize the onions up to 3 days in advance. Store in a sealed container in the fridge. Reheat before combining with pasta.
SUBSTITUTIONS: For a dairy-free version, substitute butter with olive oil and Parmesan with nutritional yeast and miso. Use gluten-free pasta as needed.
PRO TIPS: Slice onions uniformly and cook them slowly—do not rush. Use freshly grated Parmesan for a smooth, emulsified sauce. Toss pasta in the skillet for even coating.
SERVING SUGGESTIONS: Serve warm with a side salad, grilled vegetables, or a poached egg on top. Garnish with extra thyme or flaky salt for elegance.
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