Preheat the oven to 400 degrees.

Line 2 sheet pans with parchment paper.

Cut each sheet of puff pastry into 4 squares.

Lay them on the parchment and chill.

Peel the apples and cut them in half through the stem.

Discard stems and cores.

Slice the apples crosswise in ¼-inch-thick slices.

Place overlapping slices of apples diagonally across the puff pastry.

Sprinkle on the sugar and add the diced butter on top.

Bake 40 minutes until browned.

Heat the jelly and water on the stove and then brush this all over the apples and pastry.

Remove tarts with a spatula so they won't stick and serve warm!