Grease 2 x 12 hole mini muffin tins.
Preheat the oven to 180C/365F/Gas 4. Take one sheet of filo at a time and cut it in half. Then cut each half into 20 squares of approximately 4 x 4 cm (1 1/2 inch squares). Repeat with the other sheet. You should end up with a stack of filo pastry squares.
Take three squares and brush each with the melted butter. Place on square on top of the other at slight angles to each other to create a little star shape. Put the stack into one of the little holes in the muffin tin to make an empty pastry case. Repeat to create all 24 pastry cases.
Cut the brie into 48 small cubes and pop two into each pastry case. Dot with the cranberry sauce. Bake for 10-12 minutes until the pastry is golden and the cheese is bubbling. Leave to cool in the tins for a minute or two before removing carefully and serving.
They can be made ahead. Once cooked let them cool completely and store in the fridge until you are ready to serve.