Slice the boneless, skinless chicken breasts horizontally to create thinner pieces that will cook evenly.

In a large mixing bowl, combine all-purpose flour, salt, black pepper, garlic powder, onion powder, paprika, and cayenne pepper. Whisk until evenly blended.

In a separate bowl, whisk together a large egg and a splash of water until smooth.

In a third bowl, pour in your breadcrumbs, preferably panko.

Dredge each chicken piece in the seasoned flour, dip in the egg mixture, then press into the breadcrumbs.

Heat vegetable oil in a skillet over medium heat until hot. Fry the breaded chicken pieces for 4-5 minutes on each side.

Once the chicken is golden and cooked through, transfer to a plate lined with paper towels to drain excess oil.

Toast the hamburger buns in a separate pan or toaster until golden.

In a small bowl, combine mayonnaise, Dijon mustard, lemon juice, and lemon zest for the sauce.

Spread a generous layer of the sauce on the bottom half of the toasted bun, layer on the crispy chicken, followed by lettuce and tomato.

Cap off with the top half of the bun and slice in half if desired.