Season your chicken breasts with a spinkle of salt and pepper on both sides.
1 lb boneless skinless chicken breasts, kosher salt, black pepper
Heat up the olive oil in a big, oven-safe skillet over medium-high heat. Once it's hot, add the chicken and let it get a nice golden-brown color—about 4-5 minutes on each side.
2 tablespoons extra virgin olive oil
Reduce the heat to medium. Push the chicken out toward the edges of the pan and toss in your sliced onions. Cook until they're soft, which should take around 5 minutes. Next, throw in your minced garlic and cook it for about a minute more.
1 large sweet onion, 3 cloves garlic
Now, pour in the crushed tomatoes and stir in the capers and seasonings. Let the sauce come to a simmer.
1 28 ounce can crushed tomatoes, 2 tablespoons capers, 1 teaspoon dried oregano, 1 teaspoon dried basil, ½ teaspoon red pepper flakes
Cover the skillet, and let everything simmer for about 20 minutes until the chicken is cooked through and tender.
Before serving, preheat your broiler. Sprinkle mozzarella cheese over each chicken breast, then pop the skillet under the broiler just long enough for the cheese to melt and turn a light golden brown.
½ cup shredded mozzarella cheese
Finish it off with a sprinkle of fresh basil or parsley and some grated Parmesan cheese, and you're ready to dig in!
fresh basil, grated Parmesan cheese