01 - Preheat oven to 350°F. Line two baking sheets with parchment paper and set aside.
02 - Combine ground flaxseed with water in a small bowl. Let stand for 5 minutes until thickened and gelatinous.
03 - Whisk together all-purpose flour, baking powder, baking soda, and salt in a medium mixing bowl until evenly distributed.
04 - Beat softened vegan butter, granulated sugar, and brown sugar in a large bowl using an electric mixer until pale, light, and fluffy.
05 - Add the thickened flax egg, pineapple juice, and vanilla extract to the creamed butter mixture. Beat until smooth and fully incorporated.
06 - Stir the finely chopped dried pineapple into the wet mixture until evenly dispersed.
07 - Gradually add the sifted dry ingredients to the wet mixture, mixing on low speed until just combined. Avoid overmixing to keep cookies tender.
08 - Scoop tablespoon-sized portions of dough and roll into even balls. Roll each ball in granulated sugar to coat completely.
09 - Place dough balls 2 inches apart on the prepared baking sheets to allow for spreading.
10 - Bake for 11 to 13 minutes until edges are lightly golden while centers remain soft and slightly underdone.
11 - Let cookies rest on the baking sheet for 5 minutes to set, then transfer to a wire cooling rack to cool completely.