Ingredients:
2 medium onions, chopped
8 large garlic cloves, chopped
1/3 cup plus 2 teaspoons salt
2 tablespoons black pepper
1 tablespoon cayenne
8 cups water
8 chicken breast halves, 8 drumsticks, and 8 thighs (all with skin and bones; 8 to 9 lb total)
10 cups all-purpose flour
About 8 cups vegetable oil
Marinate chicken:
Marinating the chicken keeps the meat moist and imparts extra flavor. Puree onions and garlic with 1/3 cup salt, 1 tablespoon black pepper, cayenne, and 1 cup water in a food processor until smooth, then pour into a large bowl and stir in remaining 7 cups water.
Divide chicken and marinade among 3 (1-gallon) sealable plastic bags, then seal, forcing out excess air. Marinate chicken, chilled, turning bags over a few times, at least 12 hours. (If you're concerned about leaks, put bags in a large bowl.)
Dredge and fry chicken:
Whisk together flour, remaining 2 teaspoons salt, and remaining tablespoon black pepper in a large bowl, then divide between 2 large roasting pans. Drain chicken in a colander, discarding marinade, then dredge each piece of chicken in seasoned flour and leave sitting in flour. Let chicken stand 20 minutes.
Preheat oven. Line 2 large baking sheets with paper towels and set a cooling rack on each.
Heat oil in pot over moderately high heat. Knocking off excess flour, transfer 4 pieces chicken to oil (keeping batches all white meat or all dark) and fry, turning occasionally with tongs, until golden brown and cooked through, about 8 minutes for breasts or 10 to 12 minutes for drumsticks and thighs.
Lift chicken from oil with tongs, letting excess oil drip back into pot, then transfer to a rack and keep warm in oven. Dredge and fry remaining chicken in same manner, keeping it warm in oven.