So cautious was the Colonel to guard his secret that he had the idea to have two companies so neither would ever have access to the whole thing.
However this new development in the hunt for the elusive favour combination may have revealed the secret once and for all.
The Colonel's nephew Joe Ledington has a stumbled across a scrapbook previously owned by Claudia Sanders, the Colonel's second wife.
Stuck inside an envelope in the scrapbook is a handwritten note with the recipe alongside Claudia's will.
Claudia passed away in 1997 so cannot confirm the authenticity of the note.
When asked if he thought it was the original recipe Joe said: "Yeah, I do."
He added: "I don't want to get in an argument with [KFC's parent company] Yum! Brands about it but ... I'm pretty sure that it's pretty close to the original."
Yum! Brands have denied that it is the correct recipe.
Decide for yourself:
THE ORIGINAL 11 SPICES SECRET RECIPE?
(As published in The Chicago Tribune)
Prep: 30 minutes
Soak: 20-30 minutes
Cook: 15-18 minutes
Makes: 4 servings
2 cups all-purpose flour
2/3 tablespoon salt
1/2 tablespoon dried thyme leaves
1/2 tablespoon dried basil leaves
1/3 tablespoon dried oregano leaves
1 tablespoon celery salt
1 tablespoon ground black pepper
1 tablespoon dried mustard
4 tablespoons paprika
2 tablespoons garlic salt
1 tablespoon ground ginger
3 tablespoons ground white pepper
1 cup buttermilk
1 egg, beaten
1 chicken, cut up, the breast pieces cut in half for more even frying
Expeller-pressed canola oil
1. Mix the flour in a bowl with all the herbs and spices; set aside.
2. Mix the buttermilk and egg together in a separate bowl until combined. Soak the chicken in the buttermilk mixture at room temperature, 20-30 minutes.
3. Remove chicken from the buttermilk, allowing excess to drip off. Dip the chicken pieces in the herb-spice-flour mixture to coat all sides, shaking off excess. Allow to sit on a rack over a baking sheet, 20 minutes.
4. Meanwhile, heat about 3 inches of the oil in a large Dutch oven (or similar heavy pot with high sides) over medium-high heat to 350 degrees. (Use a deep-frying thermometer to check the temperature.) When temperature is reached, lower the heat to medium to maintain it at 350. Fry 3 or 4 pieces at a time, being careful not to crowd the pot. Fry until medium golden brown, turning once, 15-18 minutes. Transfer chicken pieces to a baking sheet covered with paper towels. Allow the oil to return to temperature before adding more chicken. Repeat with remaining chicken.