Preheat oven to 375F and butter, or spray, your muffin tin.
In a Microwave safe bowl, place water, lemon juice and mix well, then add apple slices and microwave on high for 3-4 minutes until soften.
In a separate bowl combine brown sugar and cinnamon.
Lightly roll the puff pastry on a lightly floured surface then cut into 4 equal parts.
Brush each part with some melted butter, sprinkle about a 1 ½ to 2 tablespoons of the brown sugar mixture on.
Layer the apple slices along the long edge of the dough, make sure that they are overlapping.
Fold bottom part of the puff pastry sheet over the apples and roll.
Bake until nicely browned, take about 30-40 minutes.