Chicken banh mi (Vietnamese sandwich)

Bahan-bahan (4 porsi)

• 2 medium carrots (, peeled cut into 2-3mm / 1/10" batons (Note 1))
• 1/2 large white radish ((daikon), peeled, cut the same as carrots (Note 1))
• 1 1/2 cups boiling water
• 1/2 cup white sugar
• 4 tsp cooking / kosher salt
• 3/4 cup rice wine vinegar ((sub apple cider vinegar))
• 4 crusty white rolls (~ 20cm/8" (Note 2))
• 2 - 3 tbsp salted butter
• 120 g / 4 oz chicken pate ((or other pate of choice))
• 4 tbsp whole egg mayonnaise or Kewpie
• 4 cups (400g/ 14oz) shredded chicken
• 2 - 3 green onion stems (, cut to bread roll length (3 pieces per Banh Mi))
• 1 cucumber (, thinly sliced lengthwise (2 slices per Banh Mi))
• 1 1/2 cups (lightly packed) coriander/cilantro sprigs
• 1/4 tsp Maggi seasoning (per Banh Mi (Note 3))
• 2 - 3 birds eye or Thai red chilli (, finely sliced)