Chop the lemongrass. Slice the cucumber into ribbons. Slice the pickled jalapeno chillies.
- 1 Make the pickled carrot and radish. Finely chop the carrot into matchsticks (or use a julienne peeler on the carrot if you have one). Slice the radish finely. Put in a bowl with the rice wine vinegar, sugar and a pinch of salt, and set aside.
- 2 Heat the oil in a pan and fry the sausages for 15-20 minutes until golden all over and cooked through. Stir the lemongrass into the bottom of the pan, followed by the honey and rice wine vinegar, season and toss the sausages in this glaze. Set aside.
- 3 Slice the baguette into four pieces then split each through the middle. Spread the base of each with 1 tbsp mayonnaise. Lay the cucumber on top. Slice the sausages in half lengthways and arrange on top then scatter over the chillies.
- 4 Top with a spoonful of pickled carrot and radish and finish with the coriander. Drizzle the sticky glaze left in the pan over each bánh mì and serve.