This creamy vegan caramelized onion pasta combines soft, golden onions with oat cream, vegan parmesan and a little chili oil. The onions become sweet and jammy in a skillet, then turn into a rich sauce that clings to every strand of pasta.

This is a stovetop recipe, with the pasta cooked separately while the onions soften. There is no blender or oven involved. Most of the cooking time goes into the onions, so give them time to develop color before adding the cream.

Ingredient Notes

The full measurements are in the recipe card. These notes help you choose ingredients and adjust the sauce to your taste.

  • Onions: Use 3 to 4 large onions, thinly sliced. Yellow onions are a good everyday choice; red onions work too and are shown in the photos. Even slices cook more consistently.
  • Pasta: The recipe uses 8 ounces of dry pasta. Spaghetti catches the onion strands nicely, while short shapes hold pockets of sauce. Cook it until just al dente.
  • Olive oil and optional vegan butter: These help the onions soften and brown. Use a wide skillet so moisture can escape.
  • Garlic and seasonings: Fresh garlic adds depth. The suggested spice amounts below give you a starting point if you prefer measurements to seasoning entirely by taste.
  • Oat cream and vegan parmesan: Choose unsweetened cooking cream and finely grated vegan parmesan. Melting and saltiness vary by brand, so keep the heat gentle and taste before adding more salt.
  • Chili oil: The original recipe uses 2 tablespoons. Start with less for a mild dish, especially if your oil contains plenty of chili pieces.
  • Water: Keep up to 1 cup of plain water nearby for the onions, adding small splashes as needed. Separately, reserve 1 cup of starchy pasta water to loosen the finished sauce. You may not need all of either.

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How To Make Caramelized Onion Pasta

Here is the visual overview. Keep the onions uncovered while they cook, and use the full instructions in the recipe card for timing and quantities.

Thinly sliced red and white onions with oil and pepper in a wide skillet
Soften the onions: Cook the thin slices in olive oil and optional vegan butter.
Soft golden caramelized onions and minced garlic in a skillet
Let them turn golden: Stir regularly, adding a splash of water only when the pan starts to catch.
Oat cream poured over caramelized onions with vegan parmesan, spices and chili oil
Make the sauce: Stir the cream, vegan parmesan, spices and chili oil into the golden onions.
Cooked spaghetti added to creamy caramelized onion sauce
Toss and serve: Add the pasta and loosen with reserved pasta water as needed.

Tips for Golden Onions and a Creamy Sauce

  • Follow the color, not just the clock. Onion size, pan width and heat all affect timing. The onions should be very soft and golden, with a sweet smell. Lower the heat if the edges darken before the centers soften.
  • Use water in small additions. A splash releases browned bits from the bottom. Let it cook off before adding more so the onions can brown rather than stay in a pool of liquid.
  • Start gently with the spices. For four servings, try 1/2 teaspoon each of sweet paprika, oregano, garlic powder and onion powder, plus 1/4 teaspoon smoked paprika. Taste the completed sauce before adjusting.
  • Keep the sauce at a gentle simmer. Stir frequently after adding the cream and vegan parmesan. If it becomes too thick, add pasta water a tablespoon or two at a time. If it is loose, toss over gentle heat briefly.
  • Finish with hot pasta. Add it straight to the sauce after draining. It will absorb more liquid as it stands, so serve while the sauce still looks a little loose.

Serving Ideas

Finish with chopped parsley and extra vegan parmesan if you like. A crisp green salad or roasted vegetables balance the creamy sauce. For a more substantial meal, fold in cooked lentils, edamame or browned smoked tofu; these are optional additions and are not included in the recipe nutrition.

Frequently Asked Questions

Yellow onions are a reliable choice for a sweet, savory sauce. Red onions, as shown in the process photos, work too and give the mixture a darker color. Slice them thinly and evenly so they soften at a similar pace.

There may still be too much water in the pan. Cook uncovered and let it evaporate, stirring as the onions begin to color. A crowded or narrow pan takes longer. Look for golden, jammy onions rather than stopping at the suggested time.

For the four-serving recipe, start with 1/2 teaspoon each of sweet paprika, dried oregano, garlic powder and onion powder, plus 1/4 teaspoon smoked paprika. These are suggested starting amounts, not a change to the original to-taste seasoning. Adjust salt and pepper after adding the vegan parmesan and chili oil.

Yes. Reduce or omit the chili oil for a milder sauce. Brands vary considerably in heat, so start with less if you are unsure and add more after tasting.

Unsweetened soy cooking cream is an alternative to oat cream; avoid sweetened creamers. For gluten free pasta, use your usual brand and check the cream, vegan parmesan, chili oil and seasonings too. Reserve cooking water and add it a little at a time, since its thickness can vary.

This version caramelizes sliced onions in a skillet and finishes with oat cream, vegan parmesan and chili oil. My roasted onion and garlic pasta uses the oven and vegan cream cheese. Choose that recipe if you want the roasting method.

Storage and Reheating

Refrigerate leftovers promptly in an airtight container for up to 3 days. Reheat gently in a skillet with a splash of water or unsweetened plant milk, stirring until hot throughout. Add more liquid only as needed because the pasta absorbs sauce in the fridge.

To get ahead, cook the onions up to 3 days in advance and keep them refrigerated. Rewarm them, then prepare the cream sauce and cook fresh pasta when you are ready to eat.

More Vegan Pasta Recipes

Creamy vegan onion pasta

Creamy Vegan Caramelized Onion Pasta

4.73 from 11 reviews
Sweet, golden onions, oat cream, vegan parmesan and chili oil make a creamy stovetop pasta sauce. Cook the pasta separately while the onions soften, then toss everything together.
Print Recipe Pin Recipe
Prep Time 10 minutes
Cook Time 40 minutes
Total Time 50 minutes
Servings: 4
Course: Main Course
Cuisine: Fusion
Calories: 660
Ingredients Equipment Method Nutrition Notes

Ingredients
 
 

For the Pasta:
  • 8 ounces Pasta of choice dry weight
  • 3-4 Large onions thinly and evenly sliced; yellow or red onions
  • 3 tbsp Olive oil
  • 1 tbsp Vegan butter optional
  • 1 tsp Sugar optional
  • 4 cloves Garlic minced
For the Sauce:
  • ¾ cup Oat cream unsweetened cooking cream
  • 1 cup Vegan Parmesan cheese finely grated
  • 2 tbsp Chili oil
  • Seasonings (to taste) Suggested starting amounts for 4 servings: 1/2 tsp each sweet paprika, dried oregano, garlic powder and onion powder, plus 1/4 tsp smoked paprika; salt and pepper to taste
For Garnish:
  • Fresh parsley chopped
Water for cooking and sauce:
  • 1 cup water up to this amount, added in small splashes to the onions as needed
  • 1 cup reserved pasta cooking water reserve before draining; add to the sauce a little at a time as needed

Equipment

  • Large skillet
  • Large Pot
  • Wooden spoon
  • Strainer

Method
 

Caramelize the Onions
  1. Heat olive oil and optional butter in a skillet over medium heat.
  2. Add the onions and sprinkle with salt and pepper. Cook until softened, about 5 minutes.
  3. Stir in the garlic and optional sugar. Continue cooking uncovered for about 25 to 30 minutes, stirring regularly, until the onions are very soft and golden. Keep up to 1 cup of plain water nearby and add a small splash when the pan starts to catch, scraping up browned bits. Let each addition evaporate before adding more. You may not need the full cup; allow extra time if the onions are still pale.
Cook the Pasta
  1. While the onions cook, boil a large pot of salted water.
  2. Cook the pasta until al dente according to the package instructions. Reserve 1 cup of pasta water, then drain.
Make the Sauce
  1. Add smoked paprika, onion powder, garlic powder, oregano, sweet paprika, and chili oil to the caramelized onions.
  2. Stir in the vegan parmesan and oat cream. Simmer gently for about 5 to 7 minutes, stirring frequently, until creamy. Add reserved pasta water a little at a time if the sauce becomes too thick. Taste before adding more salt, as vegan parmesan and chili oil vary.
Combine Pasta and Sauce
  1. Add the cooked pasta to the skillet, tossing to coat the noodles evenly. Adjust seasoning as desired.
Garnish and Serve
  1. Garnish with fresh parsley and additional Parmesan cheese if desired. Serve hot.

Nutrition

Calories: 660kcalCarbohydrates: 87gProtein: 22gFat: 24gSaturated Fat: 7gPolyunsaturated Fat: 3gMonounsaturated Fat: 13gSodium: 362mgPotassium: 387mgFiber: 6gSugar: 7gVitamin A: 275IUVitamin C: 6mgCalcium: 293mgIron: 2mg

Notes

Suggested seasonings for 4 servings: Start with 1/2 teaspoon each of sweet paprika, dried oregano, garlic powder and onion powder, plus 1/4 teaspoon smoked paprika. Adjust salt and pepper after adding the vegan parmesan and chili oil. These are starting amounts for the original to-taste seasoning.
Water: Keep up to 1 cup plain water for the onions, added gradually as needed, separate from the 1 cup of reserved pasta water for the sauce. Let the water evaporate so the onions can brown.
Timing: The onions should be golden and jammy. A smaller pan, thicker slices or lower heat can take longer than the estimated cooking time.
Storage: Refrigerate promptly in an airtight container for up to 3 days. Reheat gently with a splash of water or unsweetened plant milk until hot throughout.
Nutrition: Values are estimates per serving and vary with onion size, cream and vegan parmesan brands, salt and the amount of chili oil used. Extra toppings and optional add-ins are not included.

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