Preheat your oven to 400°F (200°C).
In a small skillet over medium heat, sauté the minced garlic and baby spinach until the leaves are completely wilted.
Transfer the spinach mixture to a small bowl and stir in the crumbled feta cheese until well combined.
Lay the chicken breast flat and use a sharp knife to cut a horizontal pocket into the thickest part, taking care not to slice all the way through.
Stuff the spinach and feta mixture into the 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 a large oven-safe skillet over medium-high heat.
Sear the chicken for 3 to 4 minutes per side until a deep golden crust forms.
Arrange the asparagus spears around the chicken in the skillet.
Place the skillet in the oven and bake for 12 to 15 minutes, or until the chicken reaches an internal temperature of 165°F.
Remove the toothpicks before serving the chicken alongside the tender roasted asparagus.