Put 2 bundles of rice noodles in a large shallow dish and cover with cold water. Leave to soak for 25 mins.
Peel and thinly slice the red onion. Peel and coarsely grate the carrot. Halve the pepper. Scoop out the seeds and white pith. Slice it into thin batons. Pop the onion, carrot and pepper into a large bowl. Quarter the Brussels sprouts, trimming away any ragged leaves. Set the sprouts aside.
Set a frying pan or wok over a medium-high heat. Add the peanuts and toast for 1 min till golden. Set aside on a board to cool.
Add 1 tbsp oil to the frying pan and slide in the quartered sprouts. Stir fry for 2-3 mins till lightly browned. Transfer them to the bowl with the veg.
Spoon the peanut butter into a small bowl. Add 1 tbsp of the tamarind paste. Squeeze in the juice from the lime. Peel and crush the garlic. Stir it into the peanut butter mix with ½ tbsp oil and a pinch of salt. Taste and add more salt if you think it needs it. Add to the veg and toss to mix.
Drain the noodles and stir them through the veg. Roughly chop the peanuts and finely chop the coriander. Scatter over the noodles and serve.