Roll out your filo pastry then place a layer out on a board.
Using a pastry brush, brush the layer with olive oil, placing the next layer of pastry on top, repeat twice more then grate your gruyere.
Sprinkle your gruyere over your pastry layers, spreading out evenly – sprinkle over some dried thyme.
Roll your pastry up into a sausage shape, then slice the ends off and slice into 6 rounds.
Add 1 tsp of olive oil to each hole in a muffin tray, adding the 6 filo pastry rounds to the holes then bake them for 15 minutes until golden brown and the cheese has fully melted.
Whilst the pastry cooks, add your oatmeal and chopped pistachios to a small saucepan, cooking on medium-low heat until golden then remove from the heat and set aside to cool.
Once your pastry is cooked, remove from the oven and leave to rest for a few minutes before serving on a small wooden board.