1 cup homemade or store-bought mayonnaise
½ cup Dijon mustard
2 tablespoons agave syrup
1 teaspoon ground cinnamon
½ teaspoon beer extract
Pinch cayenne pepper
2 large Vidalia onions
2 cups low-fat buttermilk
3½ cups all-purpose flour, divided
1 cup rice flour
4 cups soda water
One 16-ounce bottle of beer
1 teaspoon honey
Vegetable oil for deep-frying
1. Make the beer mustard: In a small bowl whisk together the mayonnaise, mustard, agave, cinnamon, beer extract and cayenne pepper. Transfer to an airtight container and refrigerate for up to 1 month.
2. Make the onion rings: Slice each onion crosswise into even ¼-inch-thick slices. Separate the slices into individual rings; remove and reserve the small 4 center rings for another use. Place the separated rings in a large, shallow bowl or baking dish and cover with the buttermilk.
3. In a large bowl whisk together 1½ cups of the flour, the rice flour, soda water, beer and honey until completely sooth. Place the remaining all-purpose flour in a large bowl and season it generously with kosher salt.
4. Fill a large, heavy-bottomed pot with at least 3 inches of oil. Attach a deep-fry thermometer to the side of the pot and heat the oil over medium-high heat to 350°.
5. Working in batches, lift the onion rings from the buttermilk and shake off the excess, transfer them to the flour mixture and toss until coated, then dip one by one into the batter, shaking off the excess, and add to the hot oil. Fry, turning the onions often with tongs, until golden brown, 3 to 4 minutes; adjust the heat as necessary to maintain the oil temperature at 350°. Use a frying spider or slotted spoon to transfer the fried onion rings to a paper towel-lined baking sheet. Sprinkle with salt while they are still warm. Serve with Beer Mustard and Sri-Rancha.