Preheat oven to 400°F (200°C)
Line baking sheet with parchment paper
Core and slice apples ⅛ inch thick
Toss apples with sugar and cinnamon
Roll out puff pastry on floured surface
Transfer to baking sheet
Score 1-inch border around edges
Arrange apple slices within border
Brush apples with melted butter
Brush border with egg wash
Bake 25-30 minutes until golden
Heat jam with water until smooth
Brush warm tart with glaze
Cool 10 minutes before serving