For the spice paste, place all of the spice paste ingredients, except the vegetable oil, into a food processor and blend to a pulp.
With the motor still running, gradually add the oil and continue to blend until you get a loose paste (you may not need to use all the oil).
For the sauce, place a frying pan over a medium heat. Add the spice paste and fry gently for 2-3 minutes.
Add the coconut milk and vegetable stock and bring to the boil. Reduce the heat and simmer for a further five minutes.
For the noodles, half-fill a deep, heavy-based pan with vegetable oil and heat until a breadcrumb sizzles and turns brown when dropped into it. (CAUTION: hot oil can be dangerous. Do not leave unattended.)
Add the tofu cubes and deep-fry for 2-3 minutes, until crisp and golden-brown. Remove with a slotted spoon and drain onto kitchen paper.
Heat the remaining one tablespoon of oil in a clean frying pan over a medium heat. Add the oyster mushrooms and fry for three minutes, or until softened.
Add the mushrooms to the sauce.
Add the sugar snap peas (or mange tout), deep-fried tofu and udon noodles to the sauce and stir well to combine.
To serve, spoon to the curry into serving bowls and garnish each with fresh coriander leaves, lime wedges and crushed peanuts, to taste.