Name: Caramelized Onion Pasta with Chilli Oil
Prep time: 10 min
Cook time: 40 min
Total time: 50 min
Cuisine: Fusion
Ingredients: 3 large yellow onions, thinly sliced 3 tablespoons olive oil 1 tablespoon butter; 0.5 teaspoon salt 1 tablespoon balsamic vinegar 10 ounces pasta (bucatini, spaghetti, or similar); 0.25 cup pasta water (reserved); 0.5 cup grated parmesan 2 teaspoons lemon juice (optional); 0.5 cup olive oil 1 teaspoon red pepper flakes 2 cloves garlic, thinly sliced 1 teaspoon paprika Pinch salt

Sweet, slow-cooked onions meet the fiery zing of homemade chilli oil in this deeply flavorful Caramelized Onion Pasta. It’s the kind of dish that feels gourmet but comes together with pantry staples, all in under an hour. Rich, glossy onions melt into pasta like silk, while that golden chilli oil brings a gentle kick and a glistening finish.

This pasta is pure comfort with attitude. Whether you’re winding down after a long day or cooking to impress, the mix of caramelized depth and spicy heat hits all the right notes. And yes, it’s just as good for a solo night in as it is for date night.

What Kind of Pasta Works Best for Caramelized Onion Pasta with Chilli Oil?

Thicker noodles like bucatini or fettuccine cling beautifully to the rich onion base and chilli oil. But honestly? Use what you love. Spaghetti, linguine, or even short pasta like rigatoni will soak up all that flavor just as well.

Ingredients for the Caramelized Onion Pasta with Chilli Oil

3 large yellow onions, thinly sliced
3 tbsp olive oil
1 tbsp butter
½ tsp salt
1 tbsp balsamic vinegar
10 oz pasta (bucatini, spaghetti, or similar)
¼ cup pasta water (reserved)
½ cup grated parmesan (plus more to serve)
2 tsp lemon juice (optional)

For the Chilli Oil:

½ cup olive oil
1 tsp red pepper flakes (adjust to taste)
2 cloves garlic, thinly sliced
1 tsp paprika
Pinch of salt

Caramelized Onion Pasta with Chilli Oil (1)

How To Make the Caramelized Onion Pasta with Chilli Oil

Step 1: Slowly Caramelize the Onions

Heat olive oil and butter in a wide pan over medium-low. Add sliced onions and salt, then cook slowly, stirring often, for 30–40 minutes until deep golden brown. Add balsamic vinegar at the end to deglaze and amplify the sweetness.

Step 2: Boil the Pasta

Cook pasta in well-salted boiling water according to package directions. Reserve ¼ cup of pasta water before draining.

Step 3: Make the Chilli Oil

In a small saucepan, heat olive oil over low heat. Add garlic and let it sizzle gently until just golden. Stir in red pepper flakes, paprika, and salt. Remove from heat and set aside.

Step 4: Bring It All Together

Toss the caramelized onions with drained pasta, reserved pasta water, and parmesan. Mix until creamy and glossy. Stir in lemon juice if using. Drizzle chilli oil over the top and gently toss again.

Step 5: Plate and Finish

Serve warm, with extra parmesan and a final swirl of chilli oil. A crack of black pepper doesn’t hurt either.

How to Serve and Store This Pasta

This dish is best served fresh, right after tossing everything together—the heat releases the most aroma from the chilli oil. Pair it with a crisp green salad and a glass of white wine for an elevated meal.

If you have leftovers, store in an airtight container in the fridge for up to 3 days. Reheat gently on the stove with a splash of water or broth to bring back the silkiness.

Frequently Asked Questions

Can I make the onions ahead of time?

Absolutely! You can caramelize the onions up to 3 days in advance and store them in the fridge. Just reheat gently when ready to use.

Is there a non-spicy version?

You can easily skip the chilli oil or reduce the red pepper flakes to make it milder. Or swap with a garlic herb oil instead.

Can I use gluten-free pasta?

Yes! This recipe works wonderfully with your favorite gluten-free pasta.

What protein can I add?

Try grilled chicken, crispy bacon, or even chickpeas for a vegetarian twist.

Is the lemon juice necessary?

No, but it does brighten the richness. If you’re skipping it, consider adding a few extra cracks of black pepper.

Want More Pasta Ideas with a Bold Flavor?

If you loved the balance of sweet and heat in this Caramelized Onion Pasta, explore more flavorful favorites from the blog:

Creamy Tuscan Sausage Pasta with sun-dried tomatoes and spinach.
Marry Me Chicken Pasta for a creamy tomato-basil dream.
Cheese Shrimp Penne Pasta with Spinach for a seafood spin with garlicky cream.
Creamy Garlic Chicken Breasts to pair with noodles or mash.
Creamy Crockpot Chicken Spaghetti if you’re after a hands-off comfort meal.

📌 Save this recipe to your Pinterest dinner board so it’s ready for your next pasta craving.

Let me know how yours turned out in the comments! Did you go heavy on the chilli oil or keep it subtle? Did you use bucatini, or get creative with your pasta shape?

I love seeing your spins and swaps. Your feedback helps everyone make the most of these recipes—ask questions, share tips, and tag @ninadishes on Pinterest to show off your plate!

Caramelized Onion Pasta with Chilli Oil

Author: Nina Klatten
Total Time: 50 minutes
Yield: 4 servings
Diet: Vegetarian

Print Recipe

Description

This Caramelized Onion Pasta with Chilli Oil is a rich and comforting pasta dish made from silky, slow-cooked onions and a bold, garlicky chilli oil. It’s full of layered flavor—sweet, savory, spicy—and takes simple ingredients to next-level deliciousness. Perfect for cozy nights or easy entertaining.

Instructions

1. Heat olive oil and butter in a wide pan over medium-low. Add sliced onions and salt, then cook slowly, stirring often, for 30–40 minutes until deep golden brown. Add balsamic vinegar at the end to deglaze.

2. Cook pasta in salted boiling water according to package instructions. Reserve 1/4 cup of pasta water, then drain.

3. In a small saucepan, heat olive oil over low. Add garlic and let it sizzle until golden. Stir in red pepper flakes, paprika, and a pinch of salt. Remove from heat.

4. Toss caramelized onions with cooked pasta, pasta water, and parmesan until creamy. Add lemon juice if using.

5. Drizzle chilli oil over the pasta and gently mix. Serve with extra parmesan and black pepper.