For the mushrooms, mix the flaxseed and water in a bowl and set aside for 10 minutes to thicken.
2
In another bowl, mix the non-dairy milk, vinegar, oyster sauce, garlic powder, basil and pepper.
3
Add the flax mixture, then pour the marinade over the mushrooms in a large ziplock bag, making sure they are well submerged.
4
Chill for at least 20 minutes or overnight.
5
Deep fry the mushrooms at 190C/375F.
6
The oil should be heated to the right temperature just as you’re about to bread the mushrooms.
7
Mix all the breading ingredients in a bowl, then coat each mushroom evenly on all sides using your hands. Fry for two to three minutes in batches, then drain on kitchen paper.
8
Combine the dressing ingredients, then halve each bun, spread with the dressing, layer with lettuce, tomato, gherkins, the mushrooms and more dressing, if you like.