This is the recipe I am currently using:
1/2 of an Athens fillo dough packet
220 gr butter (1 cup), cut in small cubes
14oz sweetened condensed milk
14 to 28oz water
1/2 tsp vanilla beans or paste (optional)
cinnamon and confectioner's sugar, for dusting
Pre-heat oven to 350F.
Arrange each of the fillo sheets on a 24cm round pan or you can choose whatever pan you like. Try to arrange them by kind of squishing them from their one side to the other. Once you have arranged all the sheets in the pan, putting them one next to the other till the pan is full of fillo sheets, spread evenly the pieces of butter on top of them.
Place the pan in the oven until the butter melts and the fillo sheets turn into golden brown. In the meantime mix the sweetened condensed milk with the 14 to 28oz of water, depending on how "full" or not you prefer your cream, I usually do a little less than the whole 28oz. You can warm the mix just a bit so that it isn't so cold when it goes in the pan. I like to add about 1/2 teaspoon of vanilla beans or paste, it creates a nice overall vanilla flavor.
Pour the milk mixture on top of the fillo sheets and continue baking until it is all absorbed by the fillo sheets. Cool for a bit and dust some cinnamon and confectioner's sugar on top!