Place chicken pieces in a bowl and cover completely with buttermilk, then refrigerate for at least 30 minutes or up to 4 hours.

In a shallow dish, combine flour, paprika, garlic powder, onion powder, salt, black pepper, and cayenne pepper. Mix thoroughly with a fork to distribute the spices evenly.

Pour vegetable oil into a large deep skillet or Dutch oven to a depth of about 2 inches, then heat to 325 degrees Fahrenheit.

Remove chicken from buttermilk and coat each piece thoroughly in the flour mixture, shaking off excess, then carefully place in the hot oil. Work in batches to avoid crowding the pan.

Fry for 12 to 15 minutes, stirring occasionally, until golden brown and the internal temperature reaches 165 degrees Fahrenheit. Transfer to paper towels to drain excess oil while you finish the remaining batches.

Place cubed potatoes in a large saucepan, cover with cold salted water, and bring to a boil over high heat. Cook for 12 to 15 minutes until a fork passes through easily, then drain thoroughly in a colander.

Return potatoes to the pan, add butter, heavy cream, and milk, then mash until you reach your preferred texture. Season generously with salt and pepper.

In a medium saucepan, melt butter over medium heat, then whisk in flour to form a paste. Cook this mixture for 1 to 2 minutes, stirring constantly, to cook out the raw flour taste while allowing the roux to turn light golden.

Gradually whisk in chicken broth and heavy cream, stirring constantly to prevent lumps from forming. Simmer for 3 to 5 minutes until the gravy thickens enough to coat the back of a spoon, then season with salt and pepper to taste.

In a skillet over medium-high heat, cook bacon strips until crispy, about 8 to 10 minutes. Drain on paper towels and crumble into bite-sized pieces once cooled enough to handle.

Divide mashed potatoes equally among four serving bowls, creating a base layer. Top each bowl with fried chicken pieces, then drizzle generously with gravy so it seeps down into the potatoes.

Sprinkle shredded cheddar cheese over the chicken while the gravy is still hot so the cheese melts slightly. Finish with crumbled bacon and sliced green onions.