Preheat the oven to 400 degrees fahrenheit and line a deep baking sheet or pan with parchment paper.
Carefully cut each chicken breast lengthwise in half, resulting in 4 thinner chicken breasts. Set aside.
Prepare a dredging station with 2 large shallow bowls or plates.
Whisk the egg into one of the bowls.
In the second bowl, combine the almond flour, salt, garlic powder, parsley, and pepper. Stir to combine.
Dredge the chicken by taking a breast and covering it in the egg. Let any excess egg drip off. Next, place the egg-coated chicken into the dry mixture and coat completely. Set aside and repeat with the remaining 3 chicken breasts.
Heat a large skillet over medium high heat and add the avocado oil. Once the oil is heated, add the coated chicken and cook for about 2 minutes per side until golden brown.
Place the browned chicken onto the baking sheet and bake for 10 minutes.
Remove from the oven and pour ¼ cup marinara sauce over each chicken breast. Top with 1 oz fresh mozzarella cheese.
Place the chicken back into the oven and cook for an additional 5-10 minutes until the cheese is melted and bubbly.