Bring a medium saucepan of water to the boil for the noodles. Halve the carrot lengthwise and thinly slice on an angle. Thinly slice the capsicum. Trim and halve the beans. Finely chop the coriander, including the stems. Coarsely chop the peanuts.
Step 2 — Make sauce
Crush or finely chop the garlic. Peel and finely grate the ginger. Separate the lime leaves, remove the central vein and very finely chop. Put the garlic, 1 tbs ginger*, lime leaves, sweet chilli sauce (if preferred, reduce or omit the sweet chilli sauce and serve it separately at the table), 1 tbs soy sauce and 1 tsp white vinegar in a bowl and whisk to combine.
Step 3 — Cook noodles
Cook the noodles in the pan of boiling water for 7 mins or until tender. Drain, then rinse under hot water to prevent the noodles from sticking.
Step 4 — Stir-fry beef
BEEF STIR-FRY OPTION Meanwhile, separate the beef stir-fry. Heat 2 tsp oil in a large deep frypan over high heat until very hot (beef stir-fry is best with hot, fast cooking; get the pan very hot before adding the beef and stick to the short cooking time). Stir-fry the beef for 1-2 mins until browned. Remove from the pan with a slotted spoon.
Step 5 — Stir-fry vegetables
Heat 2 tsp oil in the same pan over high heat. Stir-fry the carrot and capsicum for 3 mins. Add the beans and half the coriander and stir-fry for a further 2-3 mins until the vegetables are just tender.
Step 6 — Get ready to serve
Add the beef, sauce and noodles to the vegetables and toss to combine. Divide the noodle stir-fry among bowls. Scatter with the peanuts and remaining coriander to serve.