Preheat oven to 375 degrees Fahrenheit. Pat the chicken breasts dry with a paper towel and season both sides with salt and black pepper. Meanwhile, heat cast iron or oven-safe skillet over medium high heat, then add 2-3 teaspoons of oil. Sear the chicken for about 2-3 minutes per side, or until just golden brown.
While the chicken is searing, mix together the ricotta, garlic, and Italian seasoning. Once the chicken is seared, remove it and set the pan on a heat-safe area. Spoon the marinara around the bottom of the pan, then top the chicken with about 1/4 cup of the ricotta cheese mixture.
Bake at 375F for 15-20 minutes or until the ricotta has browned slightly on top and is bubbling, and the chicken registers at least 165 degrees F on a meat thermometer.
Serve warm, with the sauce scooped on top or underneath the chicken.
Notes
Using a good quality ricotta transforms this dish! My recommendations are Calabro, BelGiosio, Liuzzi, or any brand without added gums (which makes it grainy).
For marinara sauce, I recommend Rao's or Carbone's. Use a "sensitive" sauce if onions are an issue. Recommendations in the post.
I love a strong garlic flavor, so I always use 4 cloves, but I'd use 3 or less if they are very large or you're using a garlic marinara.