For 12 tartlets: warm 2 tablespoons dry white wine and put about 24 saffron threads to soak in it for 15 minutes. Brush 2 sheets of filo with melted butter and cut them into 7.5-cm / 3-inch rectangles. Press a rectangle into each depression of a buttered bun tin and put a second buttered rectangle on top with the corners at angle to the first sheet. Divide 350 g / 12 oz diced firm brie between the tarts and drizzle the saffron and soaking liquid over each. Mill plenty of coarsely ground pepper over and bake at 200°C/400°F/gas 6 for 15 minutes or until the pastry is crisp and brown round the edges and the cheese bubbling hot.