In a medium saucepan, combine chopped Honeycrisp apple, a splash of lemon juice, brown sugar, vegan butter, and pumpkin pie spice. Cook over medium heat, stirring frequently until the mixture reaches a bubbling boil and the apples soften, about 5-7 minutes.

Once bubbling, whisk together cornstarch with a bit of water to create a slurry, then add it to the apple mixture to thicken. Remove from heat and allow to cool.

In a large mixing bowl, cream together the vegan butter and both sugars until light and fluffy, about 3-4 minutes.

Then, mix in the prepared flax egg and vanilla extract, ensuring everything is well incorporated. Gradually add in the all-purpose flour, baking powder, pumpkin pie spice, and salt, stirring until a thick cookie dough forms.

Once the cookie dough is fully mixed, cover the bowl with plastic wrap or a clean kitchen towel and place it in the refrigerator. Let the dough chill for 30 minutes to 1 hour.

While the dough is chilling, preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.

After chilling, remove the dough from the refrigerator and divide it into 10 equal portions. Roll each portion into a ball and then roll in extra sugar.

Flatten each ball slightly and create an indent in the center, ready to be filled with the cooled apple mixture.

Carefully spoon the cooled apple filling into the indents of each cookie, being cautious not to overfill.

Place the baking sheet in the preheated oven and bake for 14-16 minutes, or until the edges are lightly golden and the centers appear set.

Allow the Vegan Apple Pie Cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.