In a mixing bowl, combine the chopped spinach, crumbled feta cheese, sun-dried tomatoes, cream cheese, minced garlic, oregano, salt, and pepper. Mix until all ingredients are well combined.
Preheat your oven to 375°F (190°C). Place the flattened chicken breasts between two sheets of plastic wrap and gently pound them to an even thickness.
Lay a chicken breast flat and spoon about 2-3 tablespoons of the filling mixture onto one side of the breast. Be careful not to overfill.
Starting from the filled edge, carefully roll the chicken breast tightly away from you, ensuring that the filling stays inside. Secure the ends with toothpicks to hold the roll in place.
Place the roll-ups seam-side down in a lightly greased baking dish. Brush the tops with olive oil to help brown and crisp the chicken.
Bake in the preheated oven for 25-30 minutes, or until the chicken is cooked through and reaches an internal temperature of 165°F (75°C).
Remove the roll-ups from the oven and let them rest for a few minutes before removing the toothpicks. Slice them into pinwheels or serve whole.
Notes
Serve on a platter drizzled with balsamic glaze and garnished with fresh basil leaves.