Sourdough Onion Rings (Crispy Fried Onion Rings)
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These Sourdough Onion Rings are thick, golden, and extra crispy with the kind of crunch that makes them impossible to stop eating. The sourdough discard batter and homemade sourdough breadcrumbs add so much flavor, making them taste even better than anything you’d order at a restaurant.
They’re perfect for game day, burger night, or serving with your favorite dipping sauce when you want something fun and homemade. And if you love crispy sourdough snacks, my Sourdough Fried Pickles and Sourdough Fried Chicken Tenders are two more recipes you’ll want to make next.
Quick Look: Sourdough Onion Rings
- Prep Time: 15 minutes
- Cook Time: 12–3 minutes per batch
- Total Time: 30–40 minutes
- Servings: 6
- Calories: ~ 301 kcals per serving (based on nutrition panel)
- Cook Method: Deep fried
- Flavor Profile: Thick, golden, and incredibly crunchy with a light, airy sourdough discard batter and a crispy sourdough breadcrumb coating. A flavor-packed upgrade from any restaurant version!
- Difficulty: Easy — Quick to prep and fry, ready in under 40 minutes!
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Why You’ll Love These Sourdough Onion Rings
- Super crunchy — The cold club soda in the batter and the sourdough breadcrumb coating work together to give these onion rings an incredibly light, crunchy coating that holds up well after frying. These Sourdough Fried Cheese Curds use the same crunchy sourdough coating and are just as hard to stop eating.
- A great way to use up leftovers — These homemade onion rings put both your sourdough discard and stale sourdough bread to good use. The recipe is one of the tastiest no-waste recipes ever. This Sourdough Breadcrumbs recipe is exactly how you turn that leftover bread into the coating that makes these onion rings so good.
- Quick and delicious — From slicing the onions to pulling the last batch out of the oil, these onion rings are on the table in 30 to 40 minutes, making them an easy appetizer or side dish any night of the week. These Sourdough Chicken Tenders are another quick sourdough fry that’s just as satisfying as these crispy onion rings.
Ingredients & Substitutions
* To find precise measurements, scroll to the bottom of this post to find the recipe card*
- Onions – I used a large onion (vidalia onions) because they’re sweeter but a large yellow onion (or a couple of medium sized yellow onions) will work as well. I usually slice the onions into ¼-½” thick slices.
- Sourdough Discard – Runny sourdough starter discard is best as it’s easy to whisk into the batter. You can use active sourdough starter, but the onion ring batter might not be as smooth.
- Club Soda – Cold club soda helps create a light, airy batter that fries up crisp instead of dense or heavy. You can substitute it with cold water.
- Cornstarch – A secret ingredient that helps the fried onion rings stay nice and crispy even after they’ve been fried for a little bit.
- Sourdough Breadcrumbs – I used my homemade sourdough breadcrumbs, but you can also use Panko bread crumbs if you’re in a pinch. After baking the breadcrumbs, I like to run them through the food processor again to make them super fine. These rings are probably the best thing you can do with leftover sourdough bread.
- Salt-Salt sticks better to hot fried food and really brings out the flavor. You can use kosher salt or any coarse salt you have on hand.
- Oil — You need a neutral oil with a high smoke point for frying these sourdough discard onion rings at 375°F. Canola oil and vegetable oil work great. Peanut oil is another solid option if you want a little extra flavor, and avocado oil works well for a healthier alternative.
How to Make the Best Sourdough Onion Rings
- Carefully slice the onions into 1/4″ and 1/2″ wide slices on a cutting board and separate them into individual rings.
- Gather two shallow bowls or shallow dishes. In one, combine the sourdough discard, cornstarch, club soda and spices, and whisk until smooth. Next, add the sourdough breadcrumbs to the other bowl.
- Dip the onion rings into the batter and let the excess drip off for a few seconds.
- Toss the onion rings in the sourdough breadcrumbs until fully coated. In a heavy-bottomed pot or cast iron skillet, heat 1 to 2 inches of oil to 375°F over medium-high heat.
- Working in batches, fry 3 to 6 onion rings at a time in a single layer for 2 to 3 minutes or until golden brown and crisp. Carefully transfer them from the hot oil to a wire rack set over a paper towel-lined baking sheet to drain any excess oil. Repeat with the remaining onion rings.
- Serve your deep fried onion rings with your favorite dipping sauce.
McKenna’s Helpful Tips
- Don’t overcrowd the pot. Fry in small batches of 3 to 6 rings at a time. Adding too many at once drops the oil temperature and you’ll end up with greasy, soggy onion rings instead of crispy ones.
- Keep a thermometer in the oil the whole time. The temperature of the oil can fluctuate between batches, so keeping a candy thermometer in the pot lets you know exactly when it’s back up to 375°F and ready for the next batch.
- If you don’t have sourdough breadcrumbs, use Panko. Panko breadcrumbs are a great substitute if you don’t have sourdough breadcrumbs on hand and will still give you a nice crunchy coating.
- Soak the onions in ice water first. If you find onions too strong in flavor, soak the rings in ice water for about 30 minutes before battering them. Doing that takes the edge off and makes the fried onions noticeably sweeter.
How to Store
These homemade sourdough onion rings are best eaten fresh right out of the oil while they’re still hot and crispy. If you have leftovers, let them cool completely and store them in an airtight container in the fridge for up to 3 days. They will lose their crispiness in the fridge, but reheating them the right way brings most of it back.
Reheat the onion rings in a 350°F air fryer for 3-5 minutes or in a 375°F oven for 5-8 minutes, until heated through and crispy again. Arrange the onion rings in a single layer to help them crisp up evenly, and avoid the microwave, which can make the breading soft.
Sourdough Onion Rings FAQs
You want a neutral oil that can handle high temperatures without burning. Canola oil, avocado oil, and peanut oil are all great options. Olive oil isn’t recommended since its smoke point isn’t high enough for frying at this temperature.
The most common reason is that the oil wasn’t hot enough. When the temperature drops below 375°F, the rings absorb more oil instead of frying up crisp and golden, which is why keeping a thermometer in the oil the whole time matters. Overcrowding the pot is another culprit since adding too many rings at once drops the temperature quickly. Fry in batches of 3 to 6 at a time and let the oil come back up to temperature between each batch.
The cornstarch in the batter helps these delicious onion rings stay crispy even after they’ve been sitting for a little while. Once they come out of the oil, place them on a wire rack set over a baking sheet rather than directly on paper towels. Paper towels trap steam underneath the rings which makes them soggy fast. Serving them warm right after frying is always the best way to enjoy them at their crispiest.
If you tried this Sourdough Onion Rings recipe or any other recipe on my blog, please leave a 🌟 star rating and let me know how it went in the📝 comments below. Thanks for visiting!
Sourdough Onion Rings Recipe
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Ingredients
Sourdough Onion Rings
- 1 large onion
- 200 grams discard 3/4 cup + 1 Tablespoon
- 32 grams cornstarch 1/4 cup
- 1 gram cayenne pepper 1/2 teaspoon
- salt and pepper to taste
- 140 grams club soda, cold 1 cup
- 120 grams sourdough breadrcumbs 1 cup
- neutral oil, like avocado oil for frying
Dipping Sauce (Optional)
- 120 grams mayo 1/2 cup
- 30 grams ketchup 2 Tablespoon
- 5 grams pickle juice 1 teaspoon
- 2 grams hot sauce 1/2 teaspoon
- 1 gram Worcestershire sauce 1/4 teaspoon
- 1 gram garlic powder 1/4 teaspoon
- .5 gram cayenne pepper 1/4 teaspoon
- 1 gram salt 1/4 teaspoon
Instructions
- In a heavy-bottomed pot or skillet, heat 1–2 inches of oil to 375°F over medium-high heat. I love using this frying thermometer to keep the temperature consistent.neutral oil, like avocado oil
- While the oil preheats, slice the onions into ¼–½ inch thick rounds on a cutting board, then gently separate them into individual rings. Set aside.1 large onion
- Prepare two shallow bowls. In one bowl, whisk together the sourdough discard, cornstarch, club soda, and spices until smooth. In the second bowl, add the sourdough breadcrumbs.200 grams discard, 32 grams cornstarch, 1 gram cayenne pepper, salt and pepper, 140 grams club soda, cold , 120 grams sourdough breadrcumbs
- Working one at a time, dip each onion ring into the discard batter, allowing any excess to drip off for a few seconds. Transfer the coated ring to the breadcrumb mixture and gently toss until fully coated on all sides. Place on a plate or tray and repeat with the remaining onion rings until all are covered.
- Working in batches, carefully place 3–6 onion rings into the hot oil in a single layer. Fry for 2–3 minutes, turning as needed, until golden brown and crisp.
- Using a slotted spoon or tongs, transfer the onion rings to a wire rack set over a paper towel–lined baking sheet to drain excess oil. Repeat with the remaining onion rings, allowing the oil to return to temperature between batches.
- Sprinkle the Sourdough Onion Rings with salt and serve warm with your favorite dipping sauce. Enjoy!
- Dipping Sauce : In a bowl, add the mayo, ketchup, pickle juice, hot sauce, Worcestershire sauce, garlic powder, cayenne pepper, and salt. Whisk until smooth and enjoy!120 grams mayo, 30 grams ketchup, 5 grams pickle juice, 2 grams hot sauce, 1 gram Worcestershire sauce, 1 gram garlic powder, .5 gram cayenne pepper, 1 gram salt
Notes
Tips:
- Don’t overcrowd the pot. Fry in small batches of 3 to 6 rings at a time. Adding too many at once drops the oil temperature and you’ll end up with greasy, soggy onion rings instead of crispy ones.
- Keep a thermometer in the oil the whole time. The temperature of the oil can fluctuate between batches, so keeping a candy thermometer in the pot lets you know exactly when it’s back up to 375°F and ready for the next batch.
- Soak the onions in ice water first. If you find onions too strong in flavor, soak the rings in ice water for about 30 minutes before battering them. Doing that takes the edge off and makes the fried onions noticeably sweeter.
- Add a touch of flour. If the discard batter seems to be too runny and it’s not staying on the onions at all, then you might need to add a touch more flour, start with 10 grams (1 Tablespoon) at a time, until the batter reaches the right consistency.
Ingredients & Substitutions
- Onions – I used a large onion (Vidalia) because they’re sweeter but a large yellow onion (or a couple of medium sized yellow onions) will work as well. I usually slice the onions into ¼-½” thick slices.
- Sourdough Discard – Runny sourdough starter discard is best as it’s easy to whisk into the batter. You can use active sourdough starter, but the onion ring batter might not be as smooth.
- Club Soda – Cold club soda helps create a light, airy batter that fries up crisp instead of dense or heavy. You can substitute it with cold water.
- Cornstarch – A secret ingredient that helps the fried onion rings stay nice and crispy even after they’ve been fried for a little bit.
- Sourdough Breadcrumbs – I used my homemade sourdough breadcrumbs, but you can also use Panko bread crumbs if you’re in a pinch. After baking the breadcrumbs, I like to run them through the food processor again to make them super fine. These rings are probably the best thing you can do with leftover sourdough bread.
- Salt-Salt sticks better to hot fried food and really brings out the flavor. You can use kosher salt or any coarse salt you have on hand.
- Oil — You need a neutral oil with a high smoke point for frying these sourdough discard onion rings at 375°F. Canola oil and vegetable oil work great. Peanut oil is another solid option if you want a little extra flavor, and avocado oil works well for a healthier alternative.
WOW! Talk about crunch! These Sourdough Onion Rings were a hit for the whole family and so easy to make. I hope you all love this recipe.