I love how this pasta delivers such deep flavor with just a few basic ingredients. The caramelized onions bring a natural sweetness and richness, while the chili oil adds a smoky, garlicky kick that cuts through beautifully. It’s comforting, spicy, and endlessly customizable—great on its own or served with a simple salad or protein on the side.
Ingredients
(Here’s a tip: Check out the full list of ingredients and measurements in the recipe card below.)
12 oz (340g) pasta of your choice (spaghetti, fettuccine, or penne works well)
Salt (for boiling pasta water)
2 large onions, thinly sliced
2 tablespoons olive oil
1 tablespoon butter
1 teaspoon sugar (optional, to help caramelize)
Salt and pepper, to taste
For the Chilli Oil:
1/4 cup olive oil
1 tablespoon chili flakes (adjust to taste)
1 garlic clove, minced
1/2 teaspoon smoked paprika (optional)
1/2 teaspoon salt
Optional Garnishes:
Fresh parsley, chopped
Grated Parmesan cheese
Extra chili oil
Directions
Caramelizing the Onions:
In a large skillet, I heat 2 tablespoons of olive oil and the butter over medium-low heat.
I add the thinly sliced onions with a pinch of salt, stirring occasionally to keep them from burning.
If I want to boost the sweetness, I sprinkle in the sugar. I let the onions cook for 25–30 minutes, stirring now and then, until they turn deep golden brown and jammy. Then I set them aside.
Making the Chilli Oil:
In a small saucepan, I heat the 1/4 cup of olive oil over low to medium heat.
I add the minced garlic and chili flakes, letting them infuse for 1–2 minutes—careful not to burn the garlic.
I stir in the smoked paprika and salt, then remove the pan from heat and set it aside.
Cooking the Pasta:
I bring a large pot of salted water to a boil and cook the pasta according to the package instructions until al dente—usually 8 to 10 minutes.
I reserve about 1/2 cup of the pasta water, then drain the pasta.
Assembling the Dish:
In the skillet with the caramelized onions, I add the cooked pasta and toss to combine. I use a bit of the reserved pasta water to help everything come together and evenly coat the noodles.
I pour the chili oil over the pasta and toss again until everything’s well mixed and glossy.
Serving:
I plate the pasta and garnish it with chopped parsley and a generous sprinkle of Parmesan if I’m using it.
If I want more heat, I drizzle extra chili oil over the top and serve right away.
Servings and timing
This recipe serves 4 and takes about 40–45 minutes total—15 minutes of prep time and around 25–30 minutes to cook. It’s ideal for a relaxed dinner that feels like a treat without needing a trip to the store.
Variations
Here’s how I like to tweak this recipe from time to time:
Add sliced mushrooms or spinach for more veggies.
Stir in a splash of cream or a dollop of mascarpone for a creamier version.
Use red onions or shallots for a slightly different flavor.
Top with toasted breadcrumbs or crushed nuts for extra texture.
Swap the chili flakes for Calabrian chili paste or harissa for a different heat profile.
Storage/reheating
Leftovers keep well in the fridge for up to 3 days. I reheat them in a skillet over low heat with a splash of water or oil to loosen everything up. The flavors deepen overnight, so it’s just as good—if not better—the next day.
FAQs
Can I make this dish ahead of time?
Yes, I can prep the caramelized onions and chili oil in advance. When I’m ready to serve, I just cook the pasta fresh and toss everything together.
What type of pasta works best?
I love using long noodles like spaghetti or fettuccine, but short pasta like penne or rigatoni works just as well to catch the onions and oil in every bite.
Is this dish very spicy?
The spice level is totally up to me. I use less chili if I want a milder dish, or more if I’m in the mood for heat. The chili oil can also be served on the side.
Can I make it vegan?
Yes! I just skip the butter or use a vegan alternative, and leave off the Parmesan or use a plant-based version.
Can I add protein?
Absolutely. Grilled chicken, crispy chickpeas, or sautéed shrimp all go great with this dish.
Conclusion
Caramelized Onion Pasta with Chilli Oil is a delicious balance of sweet, savory, and spicy that never fails to satisfy. It’s simple to make, packed with flavor, and easy to make your own. Whether I’m cooking for guests or just myself, this dish always brings warmth and a little kick to the table.
