Sourdough Onion Rings

If you’ve ever bitten into a perfectly golden onion ring and thought, “This could use a little more flavor,” then you’re in for a treat. Today, we’re taking the classic fried onion ring and giving it a serious upgrade with a tangy, bubbly sourdough batter. This isn’t just a snack; it’s a flavor experience. Think: crisp shell, soft sweet onion center, and that unmistakable sourdough tang in every bite.

In this post, I’ll guide you through everything you need to know to make the ultimate sourdough onion rings—whether you’re using discard or active starter. Plus, I’ll include troubleshooting tips, variations, and creative serving ideas so you can make them again and again for game day, BBQs, or even a crispy snack dinner.

Let’s get into it!

Why Sourdough in Onion Ring Batter?

Before we dive into the recipe, let’s talk about why sourdough starter makes onion rings better:

• Tangy flavor: Sourdough adds a subtle but complex tang that enhances the savory sweetness of the onion.

• Crispy texture: The natural bubbles in a bubbly starter or discard create a lighter, crunchier crust when fried.

• No waste: If you’ve been discarding starter during feedings, this is a delicious way to put it to use.

• Fermented magic: A slightly fermented batter means richer flavor and better texture, thanks to the acidity and wild yeasts.

If you're already baking sourdough bread, this recipe is a no-brainer. But even if you're new to sourdough, it’s a fun and approachable way to get started using your starter in new ways.

The Best Onions for Onion Rings

When it comes to onion rings, not all onions are created equal. You’ll want an onion that’s large, mild, and slightly sweet.

Top Choices:

• Vidalia onions: These are my go-to. Naturally sweet and ideal for frying.

• Walla Walla onions: Another sweet variety that crisps beautifully.

• Yellow onions: Slightly sharper, but still great. Let them soak in cold water to mellow their bite.

• White onions: Milder flavor and a bit sharper, but still good if that’s all you have.

No matter which you choose, make sure they’re large and firm so they slice into perfect rings without falling apart.

Tools You’ll Need

Here’s what you’ll need to make your sourdough onion rings shine:

• Large bowl (for the batter)

• Sharp knife or mandoline slicer

• Large slotted spoon or spider

• Frying thermometer

• Heavy-bottomed pot or deep fryer

• Wire rack + paper towels (for draining)

• Tongs or fork

Ingredients

Here’s the full list of what you’ll need for the batter and frying.

For the batter:

• 1 cup sourdough discard (or active starter)

• ¾ cup all-purpose flour

• 2 tablespoons cornstarch (for extra crispiness)

• 1 teaspoon baking powder

• ½ teaspoon baking soda

• ½ teaspoon garlic powder

• ½ teaspoon onion powder

• 1 teaspoon salt

• 1 teaspoon paprika (optional)

• ½ – ⅔ cup cold sparkling water or beer (adjust for thickness)

For the onions:

• 2 large Vidalia or sweet onions, sliced into ½-inch thick rings

For dredging:

• ½ cup all-purpose flour

• 1 tablespoon cornstarch

• Pinch of salt

For frying:

• 4–6 cups neutral oil (canola, vegetable, or peanut oil)

How to Make Sourdough Onion Rings – Step-by-Step

Step 1: Prep the onions

• Peel and slice your onions into ½-inch rings.

• Separate the rings and soak them in ice water for 30 minutes. This mellows the flavor and helps the batter stick better.

Step 2: Make the dredge

In a shallow bowl, whisk together:

• ½ cup flour

• 1 tbsp cornstarch

• Pinch of salt

Drain and pat your onion rings dry, then dredge them in the flour mixture. Set aside.

Step 3: Mix the batter

In a large bowl, combine:

• 1 cup sourdough discard

• ¾ cup all-purpose flour

• 2 tbsp cornstarch

• 1 tsp baking powder

• ½ tsp baking soda

• Garlic powder, onion powder, paprika, salt

Whisk to combine, then gradually add cold sparkling water or beer until the batter is thick but pourable—like pancake batter.

Let the batter sit for 10 minutes while your oil heats up.

Step 4: Heat the oil

Heat your oil to 350°F (175°C) in a heavy-bottomed pot or deep fryer. A thermometer is crucial here—too cool and the rings will be greasy; too hot and they’ll burn.

Step 5: Dip and fry

• Dip dredged onion rings into the batter, shaking off excess.

• Carefully lower into the hot oil. Don’t crowd the pot—work in batches.

• Fry for 2–3 minutes per side, or until golden and crisp.

• Use a slotted spoon to remove and drain on a wire rack over paper towels.

Repeat until all the rings are fried.

Step 6: Salt + serve

While hot, sprinkle with a pinch of sea salt. Serve immediately with your favorite dipping sauce.

Best Dipping Sauces for Onion Rings

Pair your golden sourdough onion rings with any of these killer sauces:

• Garlic aioli

• Spicy ketchup

• Chipotle mayo

• Honey mustard

• Ranch dressing

• Sriracha yogurt

• BBQ sauce

Tips for the Crispiest Onion Rings

1. Soak your onions: Ice water for 30 minutes mellows the bite and firms them up.

2. Dry thoroughly: Water = soggy. Make sure your onions are dry before dredging.

3. Use cornstarch: This helps the batter crisp up.

4. Cold batter, hot oil: Cold batter hitting hot oil = instant crisp.

5. Don’t crowd the pot: It’ll drop the oil temperature. Fry in batches.

6. Drain on a rack, not paper towels: Keeps them from steaming.

Make-Ahead and Reheating Tips

Sourdough onion rings are best served fresh, but here are some ways to prep ahead:

• Make the batter ahead: Store in the fridge for up to 24 hours. Stir and add a splash of sparkling water to loosen if needed.

• Pre-slice onions: Store covered in the fridge up to a day in advance.

• Reheat: Use an oven or air fryer at 375°F (190°C) for 5–7 minutes. Avoid microwaving—they’ll go soggy.

Sourdough Batter Variations

Want to mix things up? Try these fun batter tweaks:

• Cheesy: Add ¼ cup finely grated Parmesan to the batter.

• Spicy: Add a pinch of cayenne or a dash of hot sauce.

• Herbed: Mix in chopped fresh parsley, chives, or dill.

• Gluten-free: Use a 1:1 gluten-free flour mix and rice flour in the dredge.

What to Serve with Sourdough Onion Rings

These aren’t just a snack. Here are some pairing ideas to turn them into a full meal:

• With burgers or hot dogs

• As a crunchy side to grilled meats

• Topped on a BBQ chicken sandwich

• As part of a game-day appetizer spread

• Over salad with fried chicken

The Sourdough Twist: Why It Works

The sourdough batter makes these onion rings stand out for a few key reasons:

• Natural fermentation brings tang and complex depth.

• Airy texture means lighter rings without sogginess.

• Waste-free cooking uses up discard in a smart, delicious way.

Whether you’re a seasoned sourdough baker or a beginner with discard to spare, this recipe is a creative and satisfying twist on a beloved comfort food.

Final Thoughts

Sourdough onion rings are the ultimate comfort food with a gourmet twist. They’re crunchy, flavorful, and downright addictive. With a few pantry staples and a bubbly starter, you’ll have an unforgettable snack or side dish that’s way better than anything you’d find in the frozen aisle.

Whether you're feeding a crowd, bringing a side to a potluck, or just craving something indulgent and delicious, give these a go. And don't forget to share your creations—because once you try these, you’ll want the world to know.