Scrub the mushrooms clean, remove the stalks and outer
fringes and slice in 1cm thick pieces. Transfer to a shallow plate.
In a small mixing bowl whisk together coconut aminos,
oil, water, chilli, paprika, garlic, salt and pepper. Pour the marinade onto
sliced mushrooms, make sure each slice is evenly coated. Set aside while you
work on the rest of the sandwich components.
For the cashew ‘mayo’, add all the ingredients to a
small bowl and whisk with a fork until smooth. Check for seasoning and store in
the fridge until ready to use.
Preheat oven to 200C fan forced and line a baking
sheet with parchment paper. Place marinated mushroom slices evenly (make sure
they don’t overlap) and brush any remaining marinade on top. Bake for 15-20
minutes. Remove from the oven and toast the bread 3-4 minutes per side.
Build the sandwiches. Add a thick layer of cashew ‘mayo’
to the first bread slice, then arugula seasoned with a few drops of lemon
juice, a couple slices of tomato, a generous helping of baked Portobello slices
and close with a second bread slice with mayo on both sides. Repeat these steps
one more time so you have a three-layer sandwich. Cut the sandwich in half and