Preheat the oven to 180C. Melt the butter and let it cool.
Melt the butter in a small pan and let it cool.
Grease a 12-hole deep muffin pan. Using a silicon brush grease the holes.
Put 3 filo sheets on top of each other and cut out 10 x10 cm squares.
Lay a filo square on a chopping board, brush it with butter, then layer another square on top, slightly turned. Brush this with butter then layer another square on top, again angled.
Put this shape into one of the tin holes, slightly pushing it down with your fingers.
Repeat with the rest of the filo squares.
Crumble some cheese into each case, then add any extra ingredients you want ( nuts, lemon zest, onion jam, cranberry sauce etc). Scatter some smoked salmon on top, season with pepper, then bake for approx. 12-15 minutes, until the pastry is golden and the cheese has started to melt.
Rest in the pan for 2 minutes. Transfer the tarts to a wire rack to cool completely. Garnish with fresh herbs of your choice.
Serve warm or at room temperature.