Preheat oven to 375F and move the rack to the middle position.
Season both sides of each piece of chicken with the garlic powder and salt & pepper.
Add the oil to a skillet over medium-high heat. Once the pan is hot, sear the chicken for 5 minutes/side. Add the chicken to a greased baking dish (I used a 9x13) once both sides are seared.
Pour the marinara sauce over the chicken and use a spoon to spread it evenly over and around the chicken.
Sprinkle the parmesan over the chicken breasts, and then do the same with the mozzarella.
Bake, uncovered, for 20 minutes. If your chicken breasts are on the smaller side, I suggest doing 15 minutes.
Broil the chicken for 3-5 minutes or so until the cheese is lightly browned (watch it closely). Let the chicken rest for 5 minutes prior to serving (this will ensure it's juicy). Chicken is done when an instant read meat thermometer shows 165F in the deepest part. Its temperature will continue to rise while resting.
You can skip the step where you sear the chicken if you wish. Just place the raw chicken breasts in the baking dish, season them, and continue the recipe from step 4. I'd then cook the chicken for at least 30 minutes (or when a meat thermometer indicates it's 165F in the thickest part).
Timing on this recipe largely depends on the size of the chicken breasts, so I highly recommend using an instant read meat thermometer so you don't under or overcook the chicken.
If you have a large oven-safe skillet, feel free to use it and skip the baking dish.
Nutritional information is provided as a courtesy only and should be construed as an estimate rather than a guarantee. Ingredients can vary and Salt & Lavender makes no guarantees to the accuracy of this information.