Preheat your oven to 400°F (200°C).
Place the chicken breast between two sheets of parchment paper and pound to an even half-inch thickness, or butterfly it carefully with a sharp knife.
In a shallow bowl, whisk the egg until smooth. In a second shallow bowl, combine the almond flour, parmesan cheese, dried oregano, garlic powder, sea salt, and black pepper.
Dip the chicken breast into the egg wash, letting any excess drip off, then press firmly into the almond-parmesan mixture until fully coated on both sides.
Heat the olive oil in a medium oven-safe skillet over medium-high heat. Once the oil is shimmering, add the chicken and sear for 3-4 minutes per side until the crust is golden brown and crispy.
Spread the marinara sauce evenly over the top of the seared chicken and sprinkle with the shredded mozzarella cheese.
Transfer the skillet to the preheated oven and bake for 5-7 minutes, or until the chicken reaches an internal temperature of 165°F and the cheese is bubbly and melted.
Remove from the oven and let rest for 2 minutes. Garnish with chopped fresh parsley before serving.