Preheat oven to 350 degrees F.
If phyllo was frozen, make sure it is completely defrosted before handling it. Once removed from package, you will need to cover phyllo with waxed paper and a damp towel to prevent it from drying out. Working with 1 sheet at a time, lay out each dough sheet and brush on butter. Fold in half, brush again, fold in half, cut in half. (Each dough sheet should yield 2 rectangles, roughly 4 by 4 inches, so you will have 16 squares.) Spoon a small amount of mascarpone cheese and a spoonful of the cranberry mix in the center of each square. Bring up corners to form into a small square packet and brush more butter on top. Bake in until golden brown.