In a medium saucepan, combine the chopped Honeycrisp apple, lemon juice, brown sugar, vegan butter, and pumpkin pie spice. Cook over medium heat for about 5-7 minutes until bubbling and the apples are tender. Once bubbling, add a cornstarch slurry and stir until thickened, then set aside to cool completely.

In a large mixing bowl, cream together the vegan butter and brown sugar until fluffy, about 3-4 minutes. Add the prepared flax egg and vanilla extract, mixing well. Gradually incorporate the flour and a pinch of salt until a thick dough forms. Cover and chill for 30 minutes to 1 hour.

Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper. Once chilled, scoop tablespoon-sized cookie portions and roll into balls. Flatten slightly, creating an indent in the center for the filling.

Place the shaped cookies on the baking sheet, spaced about 2 inches apart. Fill each indent with apple pie filling. Bake for 14-16 minutes until the edges are golden, watching to avoid overbaking.

Allow cookies to cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.