Heat 1/2 tbsp of the oil in a wok or large frying pan over a medium heat, add the pork and stir fry until browned and any liquid has gone. Add the garlic, chilli, five spice, sichuan peppercorns and sugar. Stir to combine and cook for a couple of minutes. Remove from the pan onto a warmed plate and set aside.
To make the sauce place the hoisin sauce, soy sauce, peanut butter and a 100ml water in a bowl. Whisk until well combined, set aside.
Heat the remaining oil in the pan and when very hot add the pak choi and cook turning until just tender and browning.
Add the noodles and sauce and fry until warmed through. Add the warm pork mince, stir fry for a few minutes until piping hot. Remove from the heat and pile into bowls. Top with the spring onion, coriander and peanuts.