Cook the shell pasta according to package directions, then cool.

Pound the chicken breasts to a thin, even thickness.

Cook the pounded chicken with Italian seasoning, ground fennel, cayenne pepper, fresh ground pepper, and minced garlic in a pan until fully cooked.

Transfer the cooked chicken mixture, including drippings, to a food processor.

Process the chicken mixture until it forms a firm paste.

Add the spinach to the food processor and pulse for 30 seconds until incorporated.

Carefully spoon the chicken and spinach mixture into each cooked pasta shell.

Place the stuffed shells in a baking dish.

Bake at 300°F (150°C) for 10 minutes, or until the liquid is gone and the chicken starts to get crusty around the edges.

Cover the baked shells with your favorite sauce (tomato, marinara, alfredo etc.).

Serve immediately and enjoy.