Vidalia Onion Fritters

1. Place 1 3/4 cups flour, the baking powder, and salt in a large bowl and whisk to mix.
2. Place 2 cups of the milk, the eggs, vinegar, and hot sauce in another bowl and whisk until blended, then pour into the flour mixture and whisk until just blended; do not overmix. Stir in the sliced onions and let the batter rest for 30 minutes. It should be slightly thicker than heavy cream. If it isn't, sprinkle in a little more flour. If it's too thick, add a little more milk. The batter should look somewhat free-form, not doughy.
3. Preheat the oven to its lowest setting.
4. Pour vegetable oil to a depth of 4 inches into a large, heavy saucepan and heat to 375°F on a deep-fry thermometer. Drop the onion fritter batter into the hot oil by the tablespoonful, a few at a time, and fry, turning once, until the fritters are golden brown on both sides, about 3 minutes in all. The fritters will have an irregular, spiderlike look, with a few loose pieces of onion escaping here and there. Check a fritter by breaking it open to see if the center Is cooked; it it still seems unset, cook 1 minute more. Drain on paper towels. Place the fritters in the oven to keep warm while you finish frying them all. Serve on a doily-lined platter or in a lined woven basket accompanied by the dipping sauce in one or more bowls.