Sieve dry ingredients into a large bowl
Add vegan butter at room temperature into the bowl of a stand mixer, beat on low speed using the paddle attachment.
Add dry ingredients into the butter mixture, mix on medium speed to form crumbs.
Add the flax egg, mix until a smooth cookie dough forms, scrape the sides with a butter knife.
Place dough on parchment, shape into a disc, wrap and refrigerate for 1 hour.
Roll dough with a rolling pin, cut cookies with cookie cutters or shape dough balls by hand.
Place cookies on prepared baking sheets lined with sheets of parchment paper.
Air fry or bake cookies at 170°C | 340°F until lightly golden, cool on wire rack.
Melt chocolate with coconut oil using a double boiler or microwave in a small bowl.
Dip cookies into melted chocolate, add pistachios or drizzle with a piping bag fitted with a small round tip.
Let cookies set before storing in an airtight container.