Preheat the oven to 350°F and line a baking sheet with parchment paper.
In a small bowl, combine the flaxseed and water and set aside to thicken for 5 minutes.
In a medium bowl, combine the flour, baking soda, baking powder, and salt.
In a large bowl, combine the coconut oil, cane sugar, brown sugar, peanut butter, and vanilla. Stir in the flaxseed mixture and mix well.
Add the dry ingredients to the wet ingredients and stir until just combined. Chill dough for 30 minutes.
Scoop dough using a 2-inch cookie scoop and roll into balls with your hands. The dough should be on the dry side. If it’s too dry and crumbly to work with, add water, 1 teaspoon at a time, until it comes together. Flatten slightly and place on the baking sheet. Use a fork to make cross-hatch marks. Bake for 12 to 13 minutes. Remove from the oven and let sit on the baking sheet for 10 minutes before transferring to a cooling rack.