Preheat your oven to 400°F (200°C).
Finely chop the fresh spinach and mince the garlic clove.
In a small mixing bowl, combine the chopped spinach, Greek yogurt, minced garlic, and Parmesan cheese until well incorporated.
Place the chicken breast on a cutting board and use a sharp knife to cut a horizontal pocket into the thickest part, being careful not to cut all the way through.
Spoon the spinach mixture into the chicken pocket and secure the opening with two or three toothpicks.
Season both sides of the chicken breast evenly with sea salt, black pepper, and smoked paprika.
Heat the olive oil in an oven-safe skillet over medium-high heat.
Sear the chicken for 3 to 4 minutes per side until a golden-brown crust forms.
Transfer the skillet to the preheated oven and bake for 10 to 12 minutes, or until the internal temperature reaches 165°F.
Remove from the oven and let the chicken rest for 5 minutes before removing the toothpicks and serving.