Clean the chicken with lemon and vinegar, trim excess fat, and pat dry.
In a bowl, combine chicken, buttermilk, salt, and white pepper. Marinate for at least 30 minutes or up to 2 hours.
Heat oil in a deep pot to 350°F (175°C).
In a separate bowl, mix flour, onion powder, garlic powder, paprika, and seasoning.
Remove chicken from marinade, dip into flour mixture, and coat well.
Fry chicken in batches for about 7 minutes per side until golden brown and fully cooked. Rest on a rack.
Add eggs to the remaining buttermilk mixture before frying (if not already mixed).
Prepare the sauce by combining apricot preserves, chili sauce, honey, apricot juice, and sriracha. Simmer for 5–7 minutes and let cool.
Mix French toast egg mixture ingredients in a bowl.
Dip brioche slices into the mixture and cook in butter until golden on both sides.
Assemble the French toast fried chicken sandwich by placing fried chicken between two slices of French toast and drizzling with sauce.