Rosemary Chicken Sauce

Ingredients (for 2 servings)

• 3 tbsp — olive oil
• 2 lb — chicken breasts
• ½ tsp — salt
• ½ tsp — black pepper
• 2 tbsp — rosemary
• 1 tbsp — garlic
• ½ cup — onion
• ¼ tsp — red pepper flakes
• ½ cup — red wine
• 56 oz — canned crushed tomatoes