Heat a dash of oil in a lidded frying pan. Add onion and celery and cook until softened. Stir in Wattie's Tomato Paste. Pour over HEINZ [SERIOUSLY] GOOD™ Tomato & Basil Pasta Sauce and water. Stir while bringing sauce to the boil. Reduce heat and add meatballs and bay leaf. Cover. Simmer for 30-35 minutes, turning meatballs halfway during cooking, until meatballs are cooked. Serve with your favourite green vegetables.