2 yellow onions, about 1 1/2 lb. total, quartered and cut into 1/4-inch-thick strips
3 cups buttermilk 2 cups all-purpose flour
2 Tbs. kosher salt, plus more, to taste 2 cups medium-grind cornmeal
Vegetable oil for frying
Put the onions in a large bowl. Add the buttermilk and 1 Tbs. of the salt and stir to coat evenly. Refrigerate for 30 to 45 minutes. Preheat an oven to 200°F. Line a baking sheet with paper towels. Set a wire rack on another baking sheet. In a large pot over medium-high heat, pour in enough oil to fill one-third of the pot and heat to 350°F on a deep-frying thermometer. In a bowl, whisk together the flour, cornmeal and 1 Tbs. of the salt. Remove one-fourth of the onions from the buttermilk mixture, allowing the excess liquid to drip off. Place the onions in the cornmeal mixture and toss to coat evenly. Transfer to a large plate. Gently drop the coated onions into the hot oil and fry until golden brown and crisp, 3 to 4 minutes. Transfer to the paper towel-lined baking sheet to drain, then season with salt. Transfer to the wire rack-lined baking sheet and keep warm in the oven. Repeat with the remaining onions in 3 more batches. Serves 6.