Tear the oyster mushrooms into small pieces.
Mince the garlic cloves.
Heat a frying pan with a good drizzle of olive oil and add the mushrooms with a pinch of salt and pepper. Fry them for about 8 mins, on medium heat, until they start to crisp up.
Add the spinach and garlic and turn the heat down. Cook for a few more minutes until the spinach has wilted.
Remove the mushrooms from the pan and set aside. Wipe the pan clean.
Slice the filo pastry sheet in half widthways. Add half of the mushroom mix and half of the cheese and arrange into a rectangle in the middle of the pastry sheet. Brush all four sides with olive oil. Fold the long sides in and then the short sides and press lightly to seal. Try to make it tight without too much air in the sides, but not too tight that the pastry tears. Brush the whole pastry with more olive oil.
Heat the same pan on medium heat and gently add the filo pockets. Don't add any oil to the pan. Cook for about 3-5 mins, checking regularly to make sure they don't burn. Once one side is nicely browned, carefully flip and fry the other side until golden brown. Repeat with the second filo pocket.
These are best served hot and fresh but you can reheat in a dry pan if needed.
