Caramelized onion meets a kiss of chili oil in this cozy, pantry-friendly pasta that’s perfect for weeknights or laid-back weekend dinners. This Caramelized Onion Pasta with Chili Oil is simple, deeply flavored, and easy to scale for guests—think sweet, savory onions wrapped around silky spaghetti with a bright hit of chili oil to finish.
If you enjoy bold, layered flavors, you might also appreciate the texture and sauce balance in the best Peruvian chicken with creamy green sauce recipe for more inspiration on pairing rich sauces with tender proteins.
Why You’ll Love This Caramelized Onion Pasta with Chili Oil :
- Deep, comforting flavor from slow-caramelized onions with minimal effort.
- Ready in about 30–40 minutes—great for busy weeknights.
- Uses simple pantry staples; no fancy ingredients required.
- Easy to scale for meal prep or feeding a crowd.
- Vegan-friendly if you skip the Parmesan, but still rich and satisfying.
Ingredients Needed :
Pasta
- 400 grams (about 14 oz) pasta — spaghetti or fettuccine
Onions & aromatics
- 4 medium onions, sliced thinly
- 3 cloves garlic, minced
Oils & seasoning
- 4 tablespoons olive oil (divided)
- 2–3 tablespoons chili oil (adjust to taste)
- 1 teaspoon sugar
- 1 teaspoon salt
- 1/2 teaspoon black pepper
Finishes & garnish
- 1/4 cup grated Parmesan cheese (optional)
- Fresh parsley, chopped (for garnish)
Step-by-Step Instructions :
- Begin by bringing a large pot of salted water to a boil. Add the pasta and cook according to package instructions until al dente. Once cooked, reserve 1 cup of pasta water, then drain the pasta and set aside.
- While the pasta cooks, heat 2 tablespoons of olive oil in a large skillet over medium heat. Add the sliced onions and sprinkle with salt. Sauté the onions for about 10 minutes, stirring occasionally, until they begin to soften.
- Add the sugar to the onions and continue to cook for an additional 15–20 minutes, stirring frequently. The onions should turn a deep golden brown and become caramelized during this process.
- In the last few minutes of cooking the onions, add the minced garlic and cook for about 1–2 minutes until fragrant, being careful not to burn it.
- Once the onions and garlic are cooked, reduce the heat to low and add the drained pasta to the skillet. Toss the pasta with the onions and garlic until fully combined. Add reserved pasta water, a little at a time, until you reach your desired sauce consistency.
- Drizzle the remaining olive oil and chili oil over the pasta, and season with black pepper. Toss again to ensure the pasta is coated in the oils. Serve the pasta warm, garnished with grated Parmesan cheese and freshly chopped parsley.
Serving Suggestions Caramelized Onion Pasta with Chili Oil
- Serve with a crisp green salad (arugula with lemon vinaigrette) to cut the richness.
- Add a simple protein: grilled chicken, pan-seared shrimp, or roasted mushrooms for a meatless option.
- Finish with extra chili oil or crushed red pepper for more heat, or a squeeze of lemon for brightness.
- Pair with a chilled glass of crisp white wine or sparkling water with lemon for balance.
Tips for Success Caramelized Onion Pasta with Chili Oil
- Use low-medium heat for caramelizing: patience pays off—high heat risks burning.
- Stir frequently during the final stage of caramelization to prevent sticking.
- Reserve pasta water—its starch is the secret to a silky oil-based sauce.
- Slice onions uniformly so they cook evenly; a mandoline speeds this up.
- Taste and adjust salt and chili oil at the end; oils can vary in heat.
- If the sauce seems thin, cook a little longer with the pasta in the skillet to concentrate flavors.
variation (if any)
- Creamy version: stir in 1/4–1/2 cup heavy cream or a splash of pasta cooking water plus 2 tbsp butter for a richer sauce.
- Herby boost: fold in toasted breadcrumbs and torn basil or thyme for texture and aroma.
- Veggie add-ins: toss in wilted spinach, roasted bell peppers, or sautéed mushrooms for more body.
FAQs
Q: Can I make this gluten-free?
A: Yes—use your favorite gluten-free spaghetti and follow the same cooking time guidelines on the package. Reserve pasta water as directed.
Q: How long can leftovers be stored?
A: Store in an airtight container in the fridge for up to 3 days. Reheat gently with a splash of water or olive oil to loosen the sauce.
Q: Can I caramelize onions ahead of time?
A: Absolutely. Caramelized onions keep well in the fridge for up to 4 days and can be reheated before tossing with pasta.
Q: What if I don’t have chili oil?
A: Use neutral oil plus a pinch of crushed red pepper flakes or a drizzle of hot sauce to approximate the heat and flavor.
Q: Is this dish suitable for meal prep?
A: Yes—store pasta and onions separately if possible, then combine and reheat to retain texture.
Ingredients
Pasta
- 400 grams 400 grams (about 14 oz) pasta — spaghetti or fettuccine
Onions & aromatics
- 4 medium 4 medium onions, sliced thinly
- 3 cloves 3 cloves garlic, minced
Oils & seasoning
- 4 tablespoons 4 tablespoons olive oil (divided) 2 tablespoons for caramelizing onions, 2 tablespoons for finishing
- 2-3 tablespoons 2–3 tablespoons chili oil (adjust to taste)
- 1 teaspoon 1 teaspoon sugar
- 1 teaspoon 1 teaspoon salt
- 1/2 teaspoon 1/2 teaspoon black pepper
Finishes & garnish
- 1/4 cup 1/4 cup grated Parmesan cheese (optional) Omit for vegan option
- Fresh parsley, chopped (for garnish)
Instructions
Cooking Pasta
- Begin by bringing a large pot of salted water to a boil. Add the pasta and cook according to package instructions until al dente. Once cooked, reserve 1 cup of pasta water, then drain the pasta and set aside.
Caramelizing Onions
- While the pasta cooks, heat 2 tablespoons of olive oil in a large skillet over medium heat. Add the sliced onions and sprinkle with salt. Sauté the onions for about 10 minutes, stirring occasionally, until they begin to soften.
- Add the sugar to the onions and continue to cook for an additional 15–20 minutes, stirring frequently. The onions should turn a deep golden brown and become caramelized during this process.
- In the last few minutes of cooking the onions, add the minced garlic and cook for about 1–2 minutes until fragrant, being careful not to burn it.
Combining Ingredients
- Once the onions and garlic are cooked, reduce the heat to low and add the drained pasta to the skillet. Toss the pasta with the onions and garlic until fully combined.
- Add reserved pasta water, a little at a time, until you reach your desired sauce consistency.
- Drizzle the remaining olive oil and chili oil over the pasta, and season with black pepper. Toss again to ensure the pasta is coated in the oils.
- Serve the pasta warm, garnished with grated Parmesan cheese and freshly chopped parsley.
