01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - Combine ground flaxseed and water in a small bowl and let sit for 5 minutes until thickened.
03 - In a large bowl, whisk together all-purpose flour, baking soda, baking powder, and sea salt.
04 - In a separate bowl, beat together granulated sugar and melted coconut oil (or softened vegan butter) until smooth. Add flaxseed mixture, non-dairy milk, and vanilla bean seeds or extract; mix until fully incorporated.
05 - Add the dry ingredients to the wet mixture gradually, stirring just until a soft dough forms. Avoid overmixing.
06 - Scoop out tablespoon-sized portions of dough and roll them into balls. Roll each ball in granulated sugar until evenly coated.
07 - Place dough balls on prepared baking sheets, spacing them 2 inches apart. Gently flatten each ball with your palm or the bottom of a glass.
08 - Bake for 9 to 11 minutes, until the edges are set but the centers appear slightly underbaked.
09 - Let cookies cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.