Preheat oven to 180C
Brush one sheet of filo with melted butter and place on the base of the cake tin, scrunching the edges to fit. Repeat with remaining sheets.
In a small bowl, mix the mushrooms and onion slices with salt, pepper and 1 tsp olive oil.
Spoon the crème fraiche onto the base of the slice, then top with mushroom mix.
Bake in the oven for 20 minutes until the pastry is golden. Flake the Huon Hot Smoked Salmon and arrange on top, then scatted the parsley. Allow to sit for 5 minutes before serving, with a salad of mixed leaves and your favourite dressing.