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Vegan Caramelized Onion Pasta

Vegan caramelized onion pasta with a golden-amber onion sauce, silky from pasta water and finished with nutritional-yeast “parmesan.” Thinly sliced onions caramelize low and slow, then are tossed with rigatoni or spaghetti until creamy.
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Prep Time 10 minutes
Cook Time 45 minutes
Total Time 55 minutes
Servings: 4 servings
Course: Main Dish
Cuisine: Italian-American
Calories: 640
Ingredients Equipment Method Notes

Ingredients
  

Rigatoni or spaghetti
  • 1 lb rigatoni or spaghetti
Onions and aromatics
  • 4 large onions Thinly sliced.
  • 4 garlic cloves Minced.
  • 1 tbsp fresh thyme
Liquid and flavor base
  • 0.5 cup dry white wine
  • 0.5 cup pasta cooking water Reserve 1 cup during cooking; use 1/2 cup in the recipe.
  • 1 tsp balsamic vinegar
  • 0.5 tsp red pepper flakes
Fats and sauce components
  • 4 tbsp olive oil
  • 2 tbsp vegan butter
  • 4 tbsp nutritional yeast For the creamy sauce and topping.
To serve and season
  • 0.25 fresh parsley Chopped, for topping.
  • 0.25 extra nutritional yeast Optional extra for serving.
  • 0.25 salt To taste.
  • 0.25 black pepper To taste.

Equipment

  • 1 cast iron skillet

Method
 

Caramelize the onions
  1. Heat the olive oil and vegan butter in a cast iron skillet over medium-low heat for 5 minutes, then add the thinly sliced onions. Stir every few minutes as the onions begin to soften and turn glossy.
  2. Continue cooking the onions over medium-low heat for 30 minutes, stirring every few minutes, until deeply caramelized and golden. Keep the heat steady to prevent burning.
Build the onion sauce
  1. Add the minced garlic and fresh thyme to the skillet and cook for 2 minutes. Stir to coat and warm until fragrant.
  2. Pour in the dry white wine to deglaze and cook for 2 minutes. Scrape up any browned bits so the sauce turns cohesive.
  3. Stir in the balsamic vinegar and red pepper flakes. Cook for 3 minutes to mellow the flavors and deepen the color.
Cook pasta and toss
  1. Cook the rigatoni or spaghetti according to package directions until al dente. Reserve 1 cup of pasta cooking water before draining.
  2. Toss the hot pasta with the caramelized onions, nutritional yeast, and pasta water until creamy. Add more reserved water as needed for a glossy coating.
  3. Season with salt and black pepper to taste, then top with fresh parsley and extra nutritional yeast as desired. Serve immediately while the sauce clings to the pasta.

Notes

Pro tip: caramelize the onions patiently at a steady medium-low heat—stir every few minutes so they develop deep golden color without scorching. Store leftovers in the fridge up to 3 days; reheat gently with a splash of water to loosen the sauce. Freezing isn’t ideal because the onion sauce texture can break. For a soy-free option, choose a vegan butter that’s free of soy and read labels on nutritional yeast if needed for sensitivities.