In a large mixing bowl, cream together the vegan butter, brown sugar, and white sugar until light and fluffy.
Add the sourdough discard and vanilla, and mix until JUST combined. Avoid overmixing.
In another bowl, sift together all-purpose flour, baking powder, baking soda, and salt.
Add half of the dry mix to the mixing bowl with your wet ingredients, stir until just combined, then add the remainder of the flour mixture. Do not overmix.
Add the chocolate chips and stir until incorporated.
Cover and let chill in the fridge for at least 30 minutes so the dough can relax.
Preheat oven to 350F.
Scoop out cookie dough balls (approx. 40 grams) on a lined baking sheet, leaving about 2 inches between each dough ball.
Bake for 10-12 minutes. 10 min will yield a very soft, chewy cookie, 12 min will yield crisp edges with a chewy center.
Remove from oven after 10-12 min and let rest on the baking sheet for 2 minutes, then transfer to a wire rack to cool.