Pho is considered Vietnam's national dish, and its flavorful broth takes hours to perfect. Spring rolls, known as Gỏi cuốn, are a refreshing and healthy appetizer, perfect for warm weather. Banh Mi, a Vietnamese sandwich, reflects the country's French colonial past with its use of baguettes. Bun Cha, grilled pork with rice noodles, is a Hanoi specialty often served with fresh herbs and dipping sauce. Cao Lau is a noodle dish unique to Hoi An,…