Bring Out the Sweetness, Sweet Onion Spaghetti is Here | Fresh Tastes Blog | PBS Food

Bring Out the Sweetness, Sweet Onion Spaghetti is Here

sweet onion pasta

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Unfortunately many “sweet” onions at the market are high sugar cultivars, but they’ve been grown in regular soils, so it’s hard to taste the sweetness over their spiciness. But you can rid them of their pungency by leaching out the volatile sulfur compounds in a process called taming. This simply involves slicing the onions and soaking them in a few changes of water until they’re no longer spicy. Adding some baking soda to the water will help neutralize the sulfur compounds, speeding up the process.

sweet onion spaghetti

By dividing the onions in half and preparing them differently, you’re able to enjoy two different textures of onions as you eat the pasta. Half the onions are sliced paper thin with a mandoline against the grain. This helps speed up the taming process, and soaking them in water has the additional benefit of giving them a wonderfully crisp texture.

sweet onion pasta

The other half of the onions are sliced by hand with the grain, which helps preserve their shape and texture as they cook. They’re sauteed just long enough to take the edge off of them and bring out their sweetness, but not so long as to make them mushy. Toss these together with some spaghetti, pecorino romano and a little of the boiling liquid from the pasta and you have a super simple pasta that’s ultra satisfying.

sweet onion spaghetti

Sweet Onion Spaghetti

sweet onion spaghetti

Bring out the sweet onions, spaghetti, pecorino romano and you have a super simple pasta that's ultra satisfying. (Recipe Credit: Marc Matsumoto of Fresh Tastes.)



  • 8.8 ounces sweet onion (such as Vidalia or Walla Walla)
  • 5.6 ounces spaghetti
  • 2 tablespoons olive oil
  • 1.7 ounces pecorino romano
  • 1.7 ounces watercress (cut into 2-inch lengths)
  • salt and pepper to taste


  1. Peel and slice the onion(s) in half. Use a mandoline to slice half of the onions into very thin slices against the grain (the direction you would normally cut onion rings). Put the mandolined onions to a large bowl and fill with cold water. Let these onions rest until they are no longer too spicy.
  2. Slice the other half of the onions by hand with the grain into 1/4-inch thick slices.
  3. Boil the spaghetti for 1 minute less than the package directions say in salted water.
  4. While the pasta is boiling, drain and dry the mandolined onions in a salad spinner.
  5. When the pasta is about 1 minute away from being done, start heating a frying pan.
  6. When the spaghetti is done, reserve some of the cooking liquid and drain the pasta.
  7. Add the olive oil and hand-sliced onions to the frying pan and saute until they start to turn translucent, but not so long that they go limp (about 1 minute).
  8. Add 1/4 cup of the reserved pasta water and then add the pasta, half the cheese and watercress. Toss to coat evenly and then remove from the heat.
  9. Add the rest of the cheese, toss and then divide the pasta between two plates.
  10. Sprinkle some freshly cracked pepper on the pasta and grate a little extra cheese on top. Finish with a mound of tamed onions and serve.

Marc Matsumoto is the food blogger behind Fresh TastesMarc Matsumoto is a culinary consultant and recipe repairman who shares his passion for good food through his website For Marc, food is a life long journey of exploration, discovery and experimentation and he shares his escapades through his blog in the hopes that he inspires others to find their own culinary adventures. Marc’s been featured in the New York Times, Wall Street Journal, and USA Today, and has made multiple appearances on NPR and the Food Network.

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