Creamy Chicken Soup with Vegetables

Name: Creamy Chicken Soup with Vegetables
Ingredients: 1 medium yellow onion; 2 medium carrots; 2 medium stalks celery; 3 cloves garlic; 3 tablespoons unsalted butter; 3/4 teaspoon dried thyme; 1 dried bay leaf; 2 teaspoons kosher salt, divided, plus more as needed; 1/4 teaspoon freshly ground black pepper, plus more as needed; 1 1/2 pounds boneless, skinless chicken breasts or thighs (3 medium or 2 large breasts, or 5 to 6 thighs); 1/3 cup all-purpose flour; 1 (32-ounce) carton low-sodium chicken broth (about 4 cups); 2 cups whole or 2% milk; 1 medium lemon; 8 to 10 sprigs fresh parsley; 1 cup frozen peas