Preheat the oven to 350°F (177°C).
In a large bowl, mix together the flour, sugar, baking powder, and salt.
Add in the melted butter and mix until the dough comes together.
Roll out the dough on a lightly floured surface to about 1/4-inch thickness.
Cut the dough into 8-inch squares.
In a separate bowl, mix together the diced apples, cinnamon, and lemon juice.
Place the apple mixture in the center of each square of dough.
Fold the edges of the dough up and over the apple mixture, forming a pocket.
Place the dough pockets on a greased baking tray.
Sprinkle the sugar over the dough pockets.
Bake for 25-30 minutes, or until the dough is golden brown and the apples are soft.
Serve warm with a dollop of butter or a drizzle of honey.