Preheat the oven to 375°F. Lightly grease a 9 x 13 inch baking dish and set aside.

Pat the chicken breasts dry with paper towels and place them on a cutting board. Drizzle both sides with the olive oil.

In a small bowl, stir together the paprika, 1/2 teaspoon of the salt, garlic powder, and onion powder. Sprinkle the seasoning mixture evenly over both sides of the chicken and rub it in.

Using a sharp knife, cut a deep pocket into the side of each chicken breast, keeping the knife parallel to the cutting board and being careful not to cut all the way through. Set the chicken aside.

In a medium bowl, combine the cream cheese, Parmesan, mayonnaise, spinach, minced garlic, red pepper flakes, and remaining 1/2 teaspoon salt. Stir until the mixture is smooth and evenly combined.

Divide the spinach mixture evenly among the chicken breasts, spooning it into the pockets and pressing it in gently so it is well filled.

Place the stuffed chicken breasts in the prepared baking dish, seam side up, leaving a little space between each piece.

Bake uncovered for 25 minutes, or until the chicken is cooked through, the filling is hot, and an instant-read thermometer inserted into the thickest part of the chicken reads 165°F.

Remove the dish from the oven and let the chicken rest for 5 minutes before slicing or serving.