Bring a medium saucepan of water to the boil for the noodles. Halve the carrot lengthwise and thinly slice on an angle. Coarsely chop the choy sum, keeping the leaves and stems separate. Thinly slice the cabbage with a sharp knife or mandoline. Thinly slice the spring onion on an angle. Coarsely chop the peanuts.
Step 2 — Cook noodles
Cook the noodles in the pan of boiling water for 8 mins or until tender. Drain, then rinse under cold water to prevent the noodles from sticking.
Step 3 — Cook tofu
Meanwhile, heat 2 tsp oil in a medium deep frypan over medium heat. Cook the tofu for 2 mins each side or until golden and heated through. Remove from the pan.
Step 4 — Start stir-fry
Heat 1 tbs oil in same pan over high heat. Stir-fry the carrot and choy sum stems for 3-4 mins until just tender. Add the cabbage and half the spring onion and stir-fry for a further 30 secs or until tender.
Step 5 — Finish stir-fry
Add the choy sum leaves, stir-fry sauce and 2 tsp soy sauce to the vegetables and stir-fry for a further 1 min or until wilted.
Step 6 — Get ready to serve
Add the noodles to the vegetables and stir to combine. Remove the pan from the heat. Slice the tofu. Divide the noodle stir-fry and tofu among bowls and drizzle with any sauce remaining in the pan. Scatter with the peanuts and remaining spring onion to serve.