Basic Chicken Soup - olive oil

Ingredients

• 1 Tbsp. olive oil
• 1 small onion, finely chopped
• 2 medium carrots, cut into 1/4-inch thick slices
• 2 medium celery stalks, cut into 1/4-inch thick slices
• 2 (14 1/2 oz.) cans chicken broth, skimmed of fat
• 1/8 tsp. ground black pepper
• 2 medium skinless, boneless, cooked chicken breast halves (10 oz.)
• 1 c. frozen peas