Introduction

Caramelized Onion Pasta with Chili Oil is a simple yet deeply flavorful dish that perfectly balances sweet, savory, and spicy notes. The rich sweetness of slowly caramelized onions pairs beautifully with a homemade, spicy chili oil, making this pasta a memorable and comforting meal.

A close-up view of a plate of spaghetti pasta coated in a creamy, orange-colored sauce with a smooth and slightly glossy texture. The pasta strands are twisted together and topped with small bits of browned crispy crumbs and a sprinkle of finely chopped green herbs. The dish is set on a simple white plate placed on a white marbled surface. photo taken with an iphone --ar 4:5 --v 7

Ingredients

12 oz pasta (spaghetti, penne, or linguine recommended)
2 tablespoons olive oil (for sautéing onions and garlic)
1 large yellow onion, thinly sliced
3 cloves garlic, minced
Salt and pepper, to taste
3 tablespoons olive oil (for chili oil)
1 tablespoon red chili flakes
1 teaspoon paprika
1 small garlic clove, thinly sliced
1 teaspoon soy sauce
Grated Parmesan cheese, for garnish
Fresh basil or parsley, chopped, for garnish
Extra chili flakes (optional)

Instructions

Step 1: Thinly slice the yellow onion into even rings. Heat 2 tablespoons olive oil in a large skillet over medium heat. Add the onions and a pinch of salt, then cook, stirring occasionally, until they soften and turn golden, about 25-30 minutes. Add the minced garlic during the last 5 minutes of cooking and stir often to avoid burning. Season with salt and pepper, then set aside.
Step 2: In a small saucepan, warm 3 tablespoons olive oil over medium heat. Add sliced garlic and sauté for 1-2 minutes until fragrant but not browned. Stir in red chili flakes and paprika, cooking for 2-3 minutes to infuse the oil. Add soy sauce, stir, and simmer for an additional 2 minutes. Remove from heat and set aside.
Step 3: Bring a large pot of salted water to a boil. Cook pasta according to package instructions until al dente. Reserve 1 cup of pasta water, then drain the pasta.
Step 4: Toss the cooked pasta with the caramelized onions until well combined. Drizzle the chili oil over the pasta and mix thoroughly. If the pasta looks dry, add reserved pasta water gradually to loosen the sauce.
Step 5: Sprinkle grated Parmesan cheese over the pasta and garnish with chopped basil or parsley. Add extra chili flakes if desired. Serve immediately while hot.

Tips & Variations

Use long pasta shapes like spaghetti or linguine to help the chili oil coat each strand for maximum flavor.
Adjust the amount of chili flakes in the oil to match your preferred spice level.
For a vegan option, skip the Parmesan and use nutritional yeast or vegan cheese alternatives.
If you like more umami, try adding a splash of balsamic vinegar to the caramelized onions towards the end of cooking.

Storage

Store leftover pasta in an airtight container in the refrigerator for up to 3 days. Reheat gently in a skillet with a splash of water or olive oil to prevent drying out. The chili oil may firm up when cold; warm it slightly before tossing with reheated pasta.

How to Serve

The image shows a close-up of a plate with creamy spaghetti. The pasta strands are thickly covered in a light orange sauce with small bits of herbs sprinkled on top, giving a fresh green contrast. The sauce looks smooth and slightly glossy, with some browned crumbs adding texture scattered over the pasta. The plate is white and placed on a white marbled surface. photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I use other types of onions for caramelizing?

Yes, yellow onions work best for their balance of sweetness and flavor, but you can use white or red onions if preferred. Keep in mind red onions may add a slightly different taste and color.

How spicy is the chili oil, and can I make it milder?

The chili oil has a moderate heat level, which you can adjust by reducing the amount of red chili flakes or using a milder chili variety. You can also omit the chili flakes entirely for a flavorful but non-spicy oil.

Caramelized Onion Pasta with Chili Oil Recipe

Print Recipe

★★★★★

4.8 from 103 reviews

Caramelized Onion Pasta with Chili Oil is a flavorful and comforting dish that balances the sweetness of slowly caramelized onions with the spicy kick of a homemade chili oil. This easy-to-make pasta recipe uses simple ingredients like onions, garlic, olive oil, chili flakes, and paprika to create a rich, aromatic sauce that coats your favorite pasta perfectly. Garnished with Parmesan and fresh herbs, it’s an ideal meal for lunch or dinner that combines sweet, savory, and spicy notes for a truly memorable dish.

Author: Lena
Prep Time: 10 minutes
Cook Time: 35 minutes
Total Time: 45 minutes
Yield: 4 servings 1x
Category: Lunch
Method: Stovetop
Cuisine: Italian-inspired
Diet: Vegetarian

Ingredients

Scale

For the Pasta:

12 oz pasta (spaghetti, penne, or linguine)
2 tablespoons olive oil
1 large yellow onion, thinly sliced
3 cloves garlic, minced
Salt and pepper, to taste

For the Chili Oil:

3 tablespoons olive oil
1 tablespoon red chili flakes
1 teaspoon paprika
1 small garlic clove, thinly sliced
1 teaspoon soy sauce

For Garnishing:

Grated Parmesan cheese
Fresh basil or parsley, chopped
Extra chili flakes (optional)

Instructions

Caramelize the Onions: Thinly slice the onion into even rings for uniform cooking. Heat 2 tablespoons of olive oil in a large, deep skillet over medium heat. Add the onions with a pinch of salt to draw out moisture, cooking them slowly while stirring every 5-7 minutes until golden brown and soft, approximately 25-30 minutes. Add minced garlic about 5 minutes before the onions finish cooking to avoid burning and cook until fragrant. Season with salt and freshly ground black pepper, then set aside.
Make the Chili Oil: Heat 3 tablespoons of olive oil in a small saucepan over medium heat. Add the thinly sliced garlic and sauté for 1-2 minutes until fragrant but not browned. Stir in the red chili flakes and paprika, cooking for 2-3 minutes to infuse the oil with spice and smoky flavor. Add 1 teaspoon soy sauce for umami and simmer for another 2 minutes. Remove from heat and set aside.
Cook the Pasta: Bring a large pot of salted water to a boil. Cook the pasta according to package instructions until al dente. Reserve 1 cup of pasta water before draining and setting the pasta aside.
Combine Pasta and Onions: Toss the cooked pasta with the caramelized onions in the skillet or serving bowl. Drizzle the chili oil over and mix thoroughly to coat every noodle. Add reserved pasta water gradually if the mixture seems dry to achieve a glossy, smooth sauce.
Garnish and Serve: Sprinkle grated Parmesan cheese generously over the pasta for creaminess and extra flavor. Add chopped fresh basil or parsley for brightness. Optionally, top with more chili flakes for additional heat. Serve immediately while hot, alone or paired with a side salad.

Notes

Be patient while caramelizing onions; slow cooking develops their natural sweetness and deep flavor.
Adjust red chili flakes to control the heat level in the chili oil according to your preference.
Reserve some pasta water to loosen the sauce for optimal texture and coating.
Fresh herbs add a fresh contrast to the rich and spicy flavors.
This dish pairs well with a light green salad or simple grilled vegetables for a complete meal.

Keywords: caramelized onion pasta, chili oil pasta, spicy pasta, vegetarian pasta recipe, easy pasta, homemade chili oil, comfort food