Caramelized Onion Carbonara Recipe

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This caramelized onion carbonara recipe is a vegetarian take on the Roman classic. While there is no guanciale in this dish, smoked shoyu adds a great meaty flavor.

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When I was in Rome, I ate more carbonara in 4 days than any human should consume in a year. I never actually attempted making it home because I was intimidated by all of the scrambled eggs horror stories.

What goes into a carbonara?

The beauty of carbonara is in the simplicity of its ingredients. In a traditional carbonara, you need:

  • Guanciale (or pancetta, if you can’t find guanciale)
  • Eggs
  • Parmiggiano reggiano or pecorino romano
  • Freshly grated black pepper
  • Spaghetti or rigatoni, though bucatini is delicious too!

In my vegetarian version of carbonara, I swap the guanciale for caramelized onions seasoned with smoked shoyu to add a bit of smoky meatiness to the dish.

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How to make this carbonara recipe:

First, caramelize the onions. That will take around 30 minutes. Add a sprinkle of sugar and a bit of the smoked shoyu. If you don’t have smoked shoyu, you can use a touch of liquid smoke or even soy sauce or coconut aminos. Though, something with a touch of smoke will be better for this recipe.

While the onions caramelize, cook bring a large pot of salted water to a boil. Add the pasta and cook until 2 minutes under al dente. Scoop out just shy of 2 cups of the pasta cooking water.

Meanwhile, whisk together eggs, cheese, and black pepper.

Once you have the pasta cooking water ready to go, add half of it to the egg mixture to temper it with the heat of the water. Whisk until completely smooth.

Add the cooked pasta–straight from the pot–to the caramelized onions and toss to coat. Remove from the heat and add the egg mixture and stir to coat until glossy. Add a bit of the remaining pasta cooking water, as necessary, until the sauce is glossy and sticks to the noodles. You will likely not use it all, but it’s better to have too much than too little!

Serve it up with plenty more grated parmesan cheese on top and dig in!

Looking for more vegetarian recipes? Check my archives!

If you made this recipe, please rate the recipe below and leave a comment to tell me how you liked it! If you take a picture of it, please tag me on Instagram so I can feature you in my feed!

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Caramelized Onion Carbonara

This caramelized onion carbonara recipe is a vegetarian take on the Roman classic. While there is no guanciale in this dish, smoked shoyu adds a great meaty flavor.
4.34 from 15 votes
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Prep Time: 10 minutes
Cook Time: 45 minutes
Total Time: 55 minutes
Servings: 4
Calories: 629kcal


  • Wide sauté pan
  • Large pot
  • Whisk
  • Colander, if needed


  • 1 tablespoon butter
  • 1 tablespoon extra virgin olive oil
  • 2 yellow onions peeled and diced
  • 2 teaspoons sugar
  • 16 ounces spaghetti, rigatoni, or bucatini
  • 1–2 tablespoons smoked shoyu more to taste if desired
  • 4 egg yolks
  • 2 eggs
  • cup freshly grated Parmesan plus more for serving
  • Freshly grated black pepper
  • Salt


Caramelize the onions:

  • In a wide sauté pan, heat the butter and extra virgin olive oil over medium heat until the butter is frothy and bubbly. Add the diced onion and cook, stirring regularly, until the onions deepen in color. Adjust the heat as necessary to prevent it from burning. About 15 minutes in, add the sugar and smoked shoyu and continue cooking the onions for an additional 15–20 minutes until fully caramelized and deep, golden brown. Season with salt. Turn off the heat.

Cook the pasta:

  • Bring a large pot of salted water to a boil. Add the pasta and cook until 1–2 minutes under al dente. Scoop out 1½ cups of pasta cooking water and drain the pasta. Note: depending on how you time it, you may be ready to cook the eggs right as the pasta finishes cooking, in which case, you can just use tongs to transfer the pasta straight from the water to the pot of caramelized onions. If you aren't ready, just drain the pasta first!

Prepare the egg mixture:

  • In a large bowl, combine the egg yolks, eggs, parmesan, and ground black pepper to taste. Whisk for 3–5 minutes until smooth and creamy. Set aside.

Temper the egg mixture and finish the carbonara:

  • Whisking constantly, pour half of the pasta cooking water into the bowl of eggs to temper the egg mixture.
  • Return the heat on the skillet of caramelized onions to medium-low. Add the cooked pasta and toss to coat with the onions.
  • Keeping the heat on low, slowly add the egg mixture, tossing regularly, until completely coated. Turn off the heat as soon as the sauce is coated, and the pasta is warmed through (about 1–2 minutes). If the sauce is quite thick, add more of the remaining pasta cooking water until the sauce reaches your desired consistency. It should be glossy and stick to the pasta! Taste and season with salt and more freshly ground pepper to taste.

To serve:

  • Immediately serve the carbonara in shallow pasta bowls and garnish with more parmesan and black pepper. Enjoy!


Calories: 629kcal | Carbohydrates: 93g | Protein: 24g | Fat: 17g | Sodium: 207mg | Fiber: 5g | Sugar: 8g | Vitamin C: 4mg
Tried this recipe?Mention @triedandtruerecipes or tag #triedandtruerecipes so I can feature you in my feed!


      1. still like to hear what to do…. thank you.

        I had 800 gram spaghetti…..Maybe needed more liquid spaghetti water.


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