This recipe is adapted from the Williams Sonoma recipe here:
Sourdough onion rings are irresistible – crunchy, juicy and with a special sourdough tang, they disappear instantly every time we make them
The proper oil temperature is essential for producing onion rings that are crispy outside and succulent inside. If the oil does not reach 370°F, the onions will absorb fat and turn out greasy. If the oil is too hot, the food will burn. In this recipe, the onion rings are dipped in a batter that includes sourdough starter, which imparts a pleasantly tangy flavor.
2 cups sourdough starter
1/2 cup cold sparkling water
1/2 tsp. sea salt, plus more, to taste
3 large onions, peeled and cut into 1/2-inch slices
1 cup all-purpose white bread flour OR Our family has been using mashed up Pork rinds they were delicious so much flavor. Frying oil or we use real lard that we have made from animal fat. You can also buy lard from the store.
Line a baking sheet with paper towels.
Preheat an oven to 225°F
Fill a large bowl with ice cubes and place a medium bowl on top of the ice. In the medium bowl, combine the sourdough starter, sparkling water and the 1/2 tsp. salt and stir to mix. Separate the onions into rings, leaving the centers intact. Place the flour in a shallow bowl and toss the onions in the flour to coat.
In a deep fryer, pour in the oil and heat to 370°F on a deep-frying thermometer. Dip the flour-coated onion rings, one at a time, into the sourdough starter mixture, then drop them into the hot oil. Fry in a single layer, turning, if necessary, until they are golden brown. Using a slotted spoon, transfer the onion rings to the baking sheet and season with salt. Place the baking sheet in the oven and fry the next batch. Be sure the oil returns to 370ºF before adding the onions or they will be greasy.