Preheat your oven to 200°C (390°F). If you’re using store-bought puff pastry, roll it out onto a baking sheet lined with parchment paper.
In a small bowl, combine the diced apples with sugar and cinnamon. Stir until the apples are evenly coated.
Spoon the apple mixture onto the center of the puff pastry, leaving a border around the edges.
Fold the edges of the pastry over the apples, creating a rustic, open-faced tart.
Bake in the preheated oven for 10-12 minutes or until the puff pastry is golden brown and crispy, and the apples are tender.
Remove from the oven and let it cool for a few minutes before slicing and serving.