Sourdough Onion Rings
If you’ve ever wondered what to do with that extra sourdough discard hanging around in your fridge, these crispy onion rings are a great option. The sourdough starter gives the onion ring batter a subtle tang that sets them apart from the usual kind, and they’re a delicious way to use leftover sourdough starter.
With just a few pantry staples and some hot oil, you’ll have golden perfection in no time!
This simple sourdough onion rings recipe works whether you’re frying in a deep fryer (I use a Fry Daddy), a dutch oven, or a traditional cast iron skillet. The key is controlling your oil temperature—aim for around 350 degrees.
If you don’t have a built-in thermometer, a candy thermometer clipped to the side of your pot is a good idea. The Fry Daddy and similar deep fryers do this for you, which is why I love using them!
For frying, I recommend avocado oil for its high smoke point, but peanut oil is also a good choice. I don’t typically keep canola oil on hand, but it would work also.
Olive oil doesn’t handle high temperatures as well, so save that for other applications.
Cook beware—these onion rings have a way of magically disappearing that is almost spooky. I’ll pull a small batch from the fryer, set them down on the paper towel, and before I can turn around, they’ve vanished.
Everyone in my house hovers close by, waiting for that first bite of crispy, golden brown onion ring. This has become one of our family’s favorite ways to use up garden fresh onions, especially when paired with homemade hamburgers or hotdogs.
And between us friends—it’s also a good idea to use this same sourdough batter method for squash or zucchini. I’ll share that recipe soon, but for now just know it’s a great option if your garden is overflowing with squash!
Dipping Sauces for Onion Rings
The only thing better than a plate of crispy onion rings is having the perfect sauce to dunk them in. Around here, our go-to is kefir ranch—cool, creamy, and tangy, it’s the ultimate pairing for golden brown onion rings. If you like a little kick, try spicy sriracha kefir ranch, which has all the creaminess of ranch with just enough heat to make it interesting.
Other favorites at our table include a simple horseradish sauce (perfect with burgers and steak nights) and a copycat blooming onion sauce with its smoky, zesty flavor. No matter which one you choose, onion rings and dipping sauce are a match made in heaven.
Ingredients
- 2 cups sourdough starter discard (thin with regular water if needed, should be like thin pancake batter)
- 2 cups all purpose flour
- 2 tbsp onion powder
- 2 tbsp smoked paprika
- 1½ tbsp black pepper
- 1 to 1½ tbsp garlic powder
- 1 to 1½ tbsp salt, adjust to taste
- 1 large onion (sweet onions are best, though white onions will work too)
- Avocado oil, peanut oil, or canola oil for frying (enough for at least an inch of oil in your skillet or dutch oven, or fill your deep fryer to the manufacturer’s instructions)
Instructions
- Heat your oil. For a skillet or dutch oven, pour in about 1 inch of oil. For a deep fryer, fill it according to the manufacturer’s instructions. Bring the oil up slowly over medium-high heat until it reaches 350 degrees. Use a candy thermometer to check your oil temperature. Most deep fryers do this work for you and maintain a constant temperature.
- Prepare your onion. Peel a large sweet onion and slice it into ½ inch thick rings. Separate the thick rings from each other and set aside.
- Make your flour mixture. In a separate bowl, stir together the flour, onion powder, smoked paprika, garlic powder, black pepper, and salt.
- Prep your sourdough batter. Pour your sourdough starter discard into a shallow dish. If it’s extra thick straight from the fridge, thin it with a tablespoon or two of warm water until it’s like Elmer’s glue—think thin pancake batter.
- Coat the onions. Use a fork to dip each onion ring into the sourdough batter, making sure it’s fully submerged, then dredge it in the flour mixture until coated. Set aside on a wire rack while you work through the remaining onion rings.
- Fry the onion rings. Working in a small batch, carefully lower the coated rings into the hot oil. Fry for 2–3 minutes, flipping if needed, until golden brown and crispy. Remove with a slotted spoon or tongs and place on a paper towel lined plate or wire rack to drain. Repeat with the remaining onion rings, making sure the oil stays at medium heat to medium-high heat so they fry evenly.
- Serve. These homemade onion rings are best enjoyed hot with dipping sauce. My favorite pairing is kefir ranch—it’s creamy, tangy, and made with probiotic-rich kefir.
Notes
- Frying in small batches helps keep the oil at the right temperature. If you overcrowd, you’ll lose that golden perfection.
- Extra discard? This is a good way to use it up—just store the flour mix in an airtight container in the freezer and fry more rings when you’re ready.
- These make the best onion rings as a side dish for burgers, sandwiches, or just on their own for a yummy snack with plenty of dipping sauce.
Disclaimer
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Printable Recipe:
Sourdough Discard Onion Rings
Ingredients
- 2 cups sourdough starter discard thin with regular water if needed, should be like thin pancake batter
- 2 cups all purpose flour
- 2 tbsp onion powder
- 2 tbsp smoked paprika
- 1½ tbsp black pepper
- 1 to 1½ tbsp garlic powder
- 1 to 1½ tbsp salt adjust to taste
- 1 large onion sweet onions are best, though white onions will work too
- Avocado oil peanut oil, or canola oil for frying (enough for at least 1 inch of oil in your skillet or dutch oven, or fill your deep fryer to the manufacturer’s instructions)
Instructions
- Heat the oil. For a skillet or dutch oven, add about 1 inch of oil. For a deep fryer, fill according to the manufacturer’s instructions. Heat to 350°F over medium-high heat. Use a candy thermometer to monitor oil temperature.
- Prepare the onions. Peel a large sweet onion and slice into ½ inch thick rings. Separate the rings and set aside.
- Mix the flour coating. In a medium bowl, combine flour, onion powder, smoked paprika, garlic powder, black pepper, and salt.
- Prepare the sourdough batter. Pour the sourdough starter discard into a shallow dish. If it is very thick, thin with a tablespoon or two of warm water until it has the consistency of thin pancake batter.
- Coat the onion rings. Dip each onion ring into the sourdough batter, then dredge in the flour mixture until fully coated. Set on a wire rack while you prepare the rest.
- Fry the onion rings. Working in small batches, carefully place coated rings into the hot oil. Fry 2–3 minutes, turning as needed, until golden brown and crispy. Remove with a slotted spoon or tongs and transfer to a paper towel lined plate or wire rack to drain. Repeat with the remaining onion rings.
- Serve hot with dipping sauce. Kefir ranch is a favorite, but spicy sriracha kefir ranch, horseradish sauce, or blooming onion sauce are all great options.
Notes
Kitchen Tools I Recommend
I get a lot of questions about the tools I use in my kitchen, so here’s the lineup that makes frying days much easier:
- Fry Daddy deep fryer – This little workhorse keeps the oil at a steady temperature without me babysitting it. Perfect if you’re not up for fussing with thermometers and knobs.
- Cast iron skillet – If you don’t have a fryer, this is my next best choice. Cast iron holds heat beautifully and makes for even frying. Just make sure the skillet you use is deep enough for deep frying.
- Dutch oven – A great option if you want plenty of room for frying bigger batches.
- Candy thermometer – Trust me, guessing oil temp doesn’t always work. A thermometer takes out the mystery and keeps you at that golden 350.
- Wire rack – Set it over a baking sheet and your onion rings stay crisp instead of steaming on a plate.
- Slotted spoon – Makes fishing out those golden brown rings safe and easy.
These are the same tools I pull out every time onion rings are on the menu. Having the right setup really does make a difference between soggy and the crispiest onion rings!
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