In a large bowl, combine the all-purpose flour, sugar, and salt.

Add the very cold vegan butter/margarine cubes to the flour mixture. Use a cutter to chop up the butter, aiming to incorporate it but leaving slightly big chunks of margarine. It's important to have some almond-sized chunks of cold butter for a flaky crust.

Gradually add the very cold water to the mixture. Do not knead; instead, use a spatula to start putting the dough together. The dough may not look perfectly smooth, but that's okay.

The dough should be handled with care and not overworked to maintain flakiness.

Wrap the dough and refrigerate it for 1 hour.

After refrigeration, divide the dough into two parts—one for the bottom of the pie and the other for the lattice.

In a large mixing bowl, combine the sliced apples, brown sugar, vegan butter or coconut oil, vanilla and cinnamon. Mix well to coat the apples evenly.

In a small bowl, create a slurry by mixing the cornstarch with water until smooth.

Add the cornstarch slurry to the apple mixture and stir until well combined.

Transfer the apple mixture to a saucepan and cook over medium heat for a few minutes until the mixture thickens slightly. This pre-cooking step helps soften the apples and ensures a thickened filling.

Allow the pre-cooked apple mixture to cool before filling the pie crust.

Preheat your oven to 375°F (190°C).

Roll out one part of the pastry and line a pie dish with it.

Blind bake the crust by placing parchment paper and baking beads or dry beans inside. Bake at 375°F for 20 minutes.

Remove the parchment paper and beans, then bake uncovered for an additional 10 minutes, tenting the edges with foil to prevent excessive browning.

While the crust is baking, use a sharp knife or a pastry wheel to cut the rolled-out pastry into strips. The width of the strips is up to your preference, but typically they are around ½ to 1 inch wide.

Once the crust has baked for 10 minutes, remove it from the oven and fill it with the apple mixture.

Preheat the oven to 425°F.

Create a lattice pattern on top using the rolled-out pastry strips:

Lay half of the strips horizontally across the pie filling, leaving equal spacing between each strip. You can place them closer together for a tighter lattice or farther apart for a more open lattice.

Fold back every other horizontal strip, about halfway across the pie.

Lay one strip vertically over the unfolded horizontal strips.

Fold back the horizontal strips over the vertical strip.

Fold back the other set of horizontal strips (the ones that weren't folded back in the first step).

Lay another strip vertically next to the first one.

Continue this process of alternating and weaving the strips until you've covered the entire pie. Adjust the strips as needed to create a tight lattice pattern.

Trim any excess pastry hanging over the edges of the pie dish. Press the edges of the lattice strips onto the bottom crust to seal.

Use your fingers or a fork to crimp the edges of the crust, sealing the lattice to the bottom crust.

Optionally: brush the lattice with a plant-based milk and sprinkle some sugar on top for a golden finish.

Bake the pie at 425ºF for 15 minutes and then at 350ºF for 45 more minutes. Keep an eye on the borders (tent with foil if they’re browning too much).

Allow the pie to cool before serving.