Blend silken tofu until smooth and set aside.
In a pot of boiling water cook udon noodles and bok choy. Reserve 1 cup of noodle cooking water before draining.
Heat the neutral oil in a small pot and while the oil is heating up add the rest of the satay sauce ingredients to a pan/heatproof bowl. When the oil is hot, pour over the aromatics. Stir in the blended tofu and a splash of the cooking water to create a smooth creamy sauce. Adjust for seasoning.
Toss through the noodles and add bok choy. Finish with spring onion greens and chilli oil.
