Bun bo hue (spicy noodle soup)

Stock

• 400 g oxtail pieces (5-6 cm - see Tips)
• 450 - 550 g pork rashers, rind removed and meat cut into halves
• 4 stalks fresh lemongrass, white part only, bruised and cut into halves; green part reserved for later use
• 1 brown onion (approx. 120 g), cut into halves
• 2 tsp shrimp paste (see Tips)
• 1 tbsp salt
• 900 - 1000 g water, plus extra as needed (approx. 300-400 g)

Soup

• 100 g fresh bean sprouts, to serve
• 100 - 150 g purple cabbage, cut into thin slices, to serve
• 2 spring onions/shallots, cut into thin slices on the diagonal, to serve
• 8 sprigs fresh coriander, leaves only, to serve
• 6 sprigs fresh Thai basil, leaves only, to serve
• 1 fresh long red chilli, trimmed, deseeded if preferred and cut into thin slices, to serve
• 1 white onion (approx. 150 g), cut into thin slices
• water and boiling water, for soaking, plus extra as required to top up stock
• 200 g flat rice stick noodles
• 30 g oil
• 2 tsp annatto seeds (see Tips)
• 70 g eschalot
• 3 garlic cloves
• 3 tsp dried chilli flakes
• 2 tbsp fish sauce
• 1 tbsp palm sugar (2 cm cube)