Roughly chop the onion and squash the garlic and add it together with the soy milk to a sauce pan and simmer for 10 to 15 minutes.
Roughtly chop the mushrooms and put them in a container and add the cooked marinade. Cool down and leave in the fridge over night.
The next day take the mushrooms out of the liquid, drain off excess liquid and divide them into the freezer bags.
Put them in the freezer for at least 4 hours.
Take the bags out of the freezer and leave them for 10 minutes or so. This will make the mushroom easier to slice.
Slice the mushrooms into thin kebap sized slices.
Fry the mushrooms in oil for 5 minutes or so until they start to brown.
Sprinkle over the shoarma spice mixture and fry another minute or so on low heat.