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This caramelized onion pasta is rich, savory, and just a little sweet, with silky onions, garlic, chili crisp, honey, soy sauce, and parmesan coating every strand of spaghetti. It’s simple comfort food with a bold twist, ready in about 30 minutes.
Behind This Recipe
I’ve always loved how caramelized onions can completely transform a dish. They become sweet, soft, and deeply flavorful after being cooked low and slow.
Versions of caramelized onion pasta have been all over social media lately, and I completely understand why. It’s cozy, indulgent, and gives the dish an elevated feel without requiring complicated ingredients. After seeing it pop up again and again, I had to create my own version with a little more depth, adding soy sauce, honey, and chili crisp to build layers of flavor.
Tips From My Kitchen
- Low and slow wins with onions. Medium-low heat allows them time to soften and sweeten without burning. I like to get them on the stove first, then prep my other ingredients and cook the pasta simultaneously to minimize time in the kitchen.
- Salt lightly at the beginning. Add just enough to help draw out moisture and speed up caramelization. We do use soy sauce in this recipe, so you don’t want to season the onions and over-salt the dish.
- Don’t rush the sauce thickening. Let it gently simmer so it coats the back of a spoon. The sauce will continue to thicken as it cools.
- Reserve pasta water. A splash can loosen the sauce if needed.
- Finish with more chili crisp oil. It adds heat and a glossy finish right before serving.
Ingredients You’ll Need & Why
Each ingredient builds depth in this caramelized onion pasta. Be sure to review my recipe card at the bottom of the page for detailed measurements.
- White onion – Slowly caramelizes into something sweet and jammy, forming the flavor base.
- Butter & olive oil – Help the onions soften evenly and add richness.
- Garlic – Adds warmth and balance to the sweetness.
- Chili crisp – Brings heat and texture for contrast.
- Soy sauce & honey – Deepen the savory notes while enhancing the onion’s natural sweetness.
- Half and half – Creates a light cream sauce without feeling heavy.
- Parmesan cheese – Adds saltiness and helps thicken the sauce.
- Thin spaghetti – A lighter, delicate pasta that doesn’t add heaviness. Plus it twirls easily and holds onto the creamy onion sauce.
How to Make Caramelized Onion Pasta
Bring a large pot of salted water to a boil. Add the spaghetti and cook until al dente, according to package instructions. Drain and set aside, reserving about ½ cup of pasta water.
While the pasta cooks, heat olive oil and 2 tablespoons of butter in a large skillet over medium-low heat. Add the thinly sliced onion and cook, stirring frequently, for about 20 minutes. The onions should soften, shrink down, and turn lightly golden and glossy.
Add the remaining 2 tablespoons of butter and the minced garlic. Stir continuously for about 1 minute, just until fragrant.
Stir in the chili crisp, soy sauce, and honey. The mixture will become glossy and slightly sticky as it cooks together.
Pour in the half and half and add garlic powder, paprika, Italian seasoning, and black pepper. Stir well and bring to a gentle simmer. Let it cook for about 5 minutes, allowing the sauce to thicken slightly.
Add the parmesan cheese and stir until fully melted and smooth.
Add the cooked spaghetti directly into the pan. Toss thoroughly so every strand is coated in the caramelized onion sauce. If needed, add a splash of reserved pasta water to loosen the sauce.
Finish with a drizzle of chili crisp oil and fresh parsley before serving.
How to Serve and Store Leftovers
Serve this caramelized onion pasta immediately while the sauce is creamy and glossy. It pairs well with a simple green salad or roasted vegetables.
Store leftovers in an airtight container for up to 3 days. Reheat gently with a splash of milk or cream to restore creaminess.
Looking for More Pasta Recipes?
One-Pot Shrimp Scampi
Feta Tomato Pasta with Salmon
One-Pan Creamy Tuscan Pasta
Boursin Tomato Pasta with Salmon
One-Pan Butter Parmesan Pasta
One-Pan Tuscan Orzo Chicken Bake
Sun-Dried Tomato Pasta
If you make this one-pot shrimp scampi, leave a comment or rating below and tag me in photos you post on social media (@badbatchbaking). I’d love to hear how it turned out!
Caramelized Onion Pasta with Chili Oil
Ingredients
- 8 oz dry thin spaghetti
- 1 large white onion thinly sliced
- 1 tablespoon olive oil
- 4 tablespoons butter divided
- 4 cloves garlic pressed or minced
- 1-2 tablespoon chili crisp plus more for serving (depending on your heat preference)
- 2 tablespoons soy sauce
- 2 tablespoons honey
- ⅔ cup half and half coconut milk can be used for dairy free
- 1 teaspoon paprika
- ½ teaspoon garlic powder
- ½ teaspoon Italian seasoning
- ½ teaspoon black pepper
- ½ cup freshly grated parmesan
- fresh parsley for garnish
Instructions
- In a large skillet over medium-low heat, add olive oil and 2 tablespoons butter. Add sliced onion and cook, stirring frequently, for about 20 minutes until soft and lightly caramelized.
- Meanwhile, bring a large pot of salted water to a boil. Cook spaghetti until al dente. Reserve ½ cup pasta water, then drain.
- To the onions, add remaining butter and minced garlic. Cook for 1 minute until fragrant.
- Stir in chili crisp, soy sauce, and honey until combined.
- Reduce heat to low. Pour in half and half. Add paprika, garlic powder, Italian seasoning, and black pepper. Simmer 5 minutes until slightly thickened.
- Stir in parmesan until melted and smooth.
- Add cooked pasta to the skillet and toss until fully coated. Add reserved pasta water only if needed to loosen the sauce.
- Garnish with chili crisp oil and parsley before serving.
