Mince the onion and garlic. Remove the core from the garlic clove.

Cut the chicken thigh in half and even out the thickness. Season with salt and pepper.

Heat half the olive oil in a pan over medium heat. Place the chicken skin-side down and cook for 2–3 minutes until browned. Flip, cover, and cook on low heat for 5 minutes until fully cooked. Remove from the pan.

Add the remaining olive oil to the pan and sauté the onion and garlic over medium heat until softened. Add the tomato sauce ingredients and simmer on low-medium heat for 5 minutes, stirring occasionally.