Marinate the Chicken: Start by marinating the chicken breasts. In a large bowl, combine the crushed garlic, ground cumin, salt, and black pepper. Rub this mixture all over the chicken breasts. Set aside to marinate for at least 10 minutes while you prepare the rest of the ingredients.

Sear the Chicken: In a large skillet or pot, heat 1 teaspoon of olive oil over medium heat. Once hot, add the chicken breasts and sear them on each side for about 3-4 minutes until they develop a nice golden-brown crust. Don’t worry if they’re not fully cooked through at this point—they’ll finish cooking in the sauce. Remove the chicken from the skillet and set aside.

Prepare the Sofrito: In the same skillet, using the leftover oil and bits from the chicken, add the chopped red onion, green bell pepper, green chilis (if using), and celery. Sauté the vegetables over medium heat, stirring occasionally, for about 5-7 minutes until they soften and the onion becomes translucent. This combination of vegetables is known as the "Holy Trinity" of Creole cooking.

Make the Sauce: Once the vegetables are softened, pour in the tomato sauce, dried oregano, bay leaves, and 1/2 cup of water or chicken broth. Stir everything together, scraping the bottom of the skillet to lift any bits stuck from the chicken (this adds extra flavor to the sauce). Bring the mixture to a simmer, then lower the heat and cook for 10 minutes, allowing the flavors to meld together.

Thicken the Sauce: After the sauce has simmered, add the cornstarch mixture (1 teaspoon of cornstarch dissolved in 2 tablespoons of water) to the skillet. Stir well to combine and let it simmer for another 2-3 minutes. If the sauce becomes too thick, you can add a bit more water or broth to reach your desired consistency.

Cook the Chicken in the Sauce: Return the seared chicken breasts to the skillet, nestling them into the sauce. Cover the skillet and let the chicken cook in the sauce for about 20 minutes over low heat, or until the chicken is cooked through and tender. The chicken should reach an internal temperature of 165°F (74°C) when done.

Serve: Once the chicken is fully cooked, remove the bay leaves and discard it.