Preheat the oven to 350°F (177°C). Line a large baking sheet with parchment paper. Set aside.
In a small bowl, combine the ground flaxseed and water. Let it thicken for a few minutes.
In a medium to large bowl, add the vegan butter, brown sugar and granulated sugar. Stir until well combined, about 15-30 seconds.
Add the vanilla extract, almond extract and flaxseed mixture to the wet ingredients. Combine.
To the same bowl, add the flour, cornstarch, baking soda and salt. Stir the dry ingredients together at the top before incorporating into the wet ingredients. Stir until just combined.
Fold in the chocolate chips and chopped pistachios.
Roll the dough into 12 balls and place them on the prepared baking sheet, keeping some distance between each cookie as they will spread.
Bake for 11 to 13 minutes or until lightly golden. Sprinkle each cookie with a small pinch of flaky salt while they’re still warm. Let them cool for at least 10 minutes before eating.