Add frozen cherries, sugar and vanilla essence to a saucepan. Cook on medium heat for 5 minutes, stirring frequently. Gently break apart cherries with a spatula. Mix together the arrowroot powder and water to form a paste.

Add the mixture to the cooked cherries, stirring as you pour it in. Bring to the boil and remove from heat. Allow to cool. Preheat oven to 190°C /gas mark 5 and grease a muffin tin.

Take three pastry sheets and cut each into four squares. Melt the butter and brush the pastry on each side and line six holes with two squares in each. Add one tablespoon of cherry filling to each. Fold the filo pastry edges over the top of the cherry filling to loosely close.

Brush each tart with additional butter. Bake in the oven for 10 - 15 minutes, until the pastry looks light golden brown all over. Remove from heat and transfer to cooling rack. Beware the cherry filling is very hot. Once cooled, dust with powdered sugar. Serve warm or at room temperature.