Preparation Season chicken with salt and pepper. Cover; chill at least 4 hours or overnight. Combine flour, cornstarch, 1/2 teaspoons salt, and 1/2 teaspoons pepper in a large bag. Working in batches, shake chicken in bag to coat well; transfer to a plate. Fit a large deep heavy straight-sided skillet with a deep-fry thermometer; add oil to measure 3/4". Heat over medium-high heat until thermometer reads 350°F. Working in batches and maintaining oil at 350°F, fry chicken and fatback (if using) until crisp and chicken is cooked through, 5-7 minutes per side. Drain on paper towels and season with salt.