Prepare the noodles as per the instructions on the packet and then refresh them in cold water prior to starting to stir fry.
Roughly chop the greens for the pak choi and then cut the stalks into 5-6mm (¼") lengths.
Peel and mash the garlic cloves into a paste.
Heat a wok over a high heat and toast the Szechuan pepper for 1-2 minutes, then crush it in a pestle and mortar.
Mix together all of the ingredients for the sauce along with the toasted and crushed Szechuan pepper and set aside.
Cut the white part of the spring onions into lengths about 5cm (2") long and then shred them lengthways as finely as you can. Drop the shredded spring onions in cold water.
Finely slice the green parts of the spring onions.
Heat a wok over a very high heat, and when it begins to shimmer, add the vegetable oil followed by the pork and stir fry for 2 minutes.
Throw in the pak choi stems and cook for a further 2 minutes.
Pour in the sauce, and quickly combine everything.
Add the pak choi greens, peanuts, sesame oil and drained noodles and stir fry until everything is hot.
Drain the spring onions on kitchen paper and serve them as a garnish to the noodles.