Crumble the tempeh into small pieces. Roughly chop the mushrooms. Finely slice the spring onions and set aside some of the green tips for topping.
Fry the tempeh, spring onions and mushrooms in a large frying pan on medium high heat with a good splash of sunflower oil and a pinch of salt. Stir fry for about 10 minutes until starting to crisp up.
While the tempeh is cooking, make the marinade. Mince the ginger and garlic and add to a small bowl. Add the rest of the ingredients and whisk well.
In a separate pan, cook the spinach with a pinch of salt, on medium heat until wilted.
Add the marinade to the tempeh and cook for another 5-10 minutes until the tempeh and mushrooms are browned on the edges and starting to crisp up.
Cook the noodles according to package instructions, then drain.
Whisk together all of the ingredients for the noodle sauce and toss the noodles through it.
Serve the saucy noodles in bowls, then top with the tempeh, reserved spring onion, sesame seeds, some extra chilli oil and the wilted spinach.
