In a food processor, add the butter and sugar and run until combined. Add the egg and run until combined as well.

Add the flour and pulse until just combined. Tip out onto a floured surface and knead together into a flat disk. Wrap with plastic and refrigerate while you prepare the filling.

Prepare the apples by peeling and cutting into fourths. Remove the core and cut each fourth into thirds, giving you 12 slices from one apple. The slices should be about 1cm thick. Repeat for the other 3 apples.

In a separate container, mix the sugar and cinnamon.

Sprinkle the apple slices with the cinnamon sugar and toss to coat evenly.

Melt the butter in a large frying pan over medium high heat. Add the apple slices to the pan, scraping out all the cinnamon sugar from the bowl.

Cook the apple slices until they are slightly soft and the cinnamon sugar, juice from the apples, and butter have made a slightly thick caramel sauce. Remove from heat and transfer to a separate bowl to cool down completely.

Once the apples have cooled, prepare your crust dough. If your dough is coming out of the refrigerator, let it sit at room temp for about 10 minutes so it is easier to work with. Roll the crust dough to about 3mm thick.

Gently lay the pie sheet over a pie pan, making sure it is right against the pan. Trim off the excess, leaving about 2cm of overhang, and bring together to reroll for the lattice. If you are using frozen pie sheet, it may be easier to use another sheet instead of rolling the excess together.

Once you’ve rolled the excess to 3mm as well, cut strips about 3cm or 1.25 inches wide for the lattice. Make sure each strip is long enough to cover the length of the pie. You will need 6 strips.

Begin making the lattice. Lay down one strip in the middle of the pie, then lay down another strip perpendicular to the first strip, also in the middle of the pie. The two strips should look like a crosshair aiming at the center of the pie.

Lay down the next strip on top of the strip on top, with a gap about as wide as the strip. Repeat on the opposite side, and you’ve finished laying down the strips in this direction.

Carefully fold down the flap of the first strip you placed and place another strip down, on top of and intersecting the two strips that were laid down in step 10. Unfold the first strip and that side is done. Repeat with the other half and remaining strip and the lattice is complete.

Fold the excess dough over onto the edge of the lattice, lining the fold up with the edge of the pan, and crimp to seal the crust in place.

Beat the egg to create an egg wash and carefully brush it over the top of the apple pie. Sprinkle it with some granulated sugar.

Bake at 375°F/190°C for 40-45 minutes. Occasionally keep an eye on the apple pie as it bakes. You may need to create a cover using aluminum foil to wrap around the edge of the pie to slow down the browning on the edges and allow the center to bake more.

Once the pie is golden brown, remove from the oven. Allow to mostly cool before you cut into it, and the apple pie is done! 完成です！