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–+ servings
Caramelized onion pasta in a black skillet seen from above, casarecce coated in golden onions and grated parmesan, next to a box grater and a wedge of parmesan on a dark linen napkin.

Caramelized Onion Pasta

Caramelized onion pasta with jammy, slow-cooked onions, casarecce and parmesan, made creamy with starchy pasta water instead of cream.
Prep Time 10 minutes
Cook Time 45 minutes
Total Time 55 minutes
Choose Serving Size 4 servings

Equipment

  • Large pot
  • Large skillet
  • Wooden spoon
  • Grater

Ingredients 

  • 14 oz casarecce pasta or penne, fusilli
  • 4 yellow onions large, chopped or thinly sliced, about 2 lb / 1 kg
  • 3 tbsp butter
  • 2 tbsp olive oil
  • 1 tsp brown sugar
  • 2 cloves garlic minced
  • Salt to taste
  • Black pepper freshly ground
  • ½ cup parmesan grated, plus more to serve
  • Thyme leaves fresh, to garnish

Instructions

  • Heat the butter and olive oil in a large, wide skillet over medium heat. Add the onions and a pinch of salt and cook for 10 to 15 minutes, stirring now and then, until soft and translucent.
  • Stir in the brown sugar and lower the heat to medium-low. Cook for 20 to 25 minutes more, stirring every few minutes, until the onions are deep amber and jammy. Whenever the bottom of the pan browns or the onions stick, add 1 to 2 tablespoons of water and scrape up the browned bits with a wooden spoon.
  • Meanwhile, bring a large pot of salted water to a boil and cook the pasta until al dente, following the package directions. Before draining, reserve 1 cup (240 ml) of the cooking water.
  • Add the garlic to the onions and cook for 1 to 2 minutes, until fragrant. Season with salt and black pepper.
  • Add the drained pasta and about half of the reserved water to the skillet and toss over low heat for 1 to 2 minutes. Take the pan off the heat, add the parmesan and toss vigorously, adding more pasta water a splash at a time, until the sauce is glossy and creamy.
  • Serve right away, topped with more parmesan and fresh thyme leaves.

Notes

Don't rush the onions: high heat browns the outside before they turn sweet. Chop them or slice them thinly, as you prefer. The brown sugar is optional, and a teaspoon is enough. Traditional Parmigiano Reggiano is made with animal rennet, so choose a vegetarian hard cheese if you eat strictly vegetarian. Vegan: use vegan butter or extra olive oil and 2 to 3 tablespoons of nutritional yeast instead of parmesan. The caramelized onions keep in the fridge for up to 4 days.