In a saute pan over medium heat add the olive oil and garlic. Saute for one minute and add the spinach. Mix well until the spinach is completely wilted. Add half the salt and pepper to the spinach before taking of the heat. Mix the spinach together with the ricotta cheese, herbs, egg, and the rest of the salt and pepper.
Butterfly the chicken and stuff with the ricotta mixture. Add 1 tbsp of olive oil to a saute pan on high heat. Cook the chicken for about 5 minutes on each side. Place the pan in a 375 degree oven and bake for another 20-25 minutes.
Remove the chicken from the oven and place the marinara sauce and cheese on top and return to the oven, on broil for about 3-5 minutes or until the cheese begins to bubble and brown.
Remove from the oven and let sit for 5-10 minutes. Slice the chicken breasts in about 1.5 inch slices. Serve over pasta, rice, or zucchini noodles.