Preheat oven to 350ºF.
Line a large baking tray with parchment paper and set aside.
In a small bowl, create your flax eggs by adding 2 tbsp of flax seeds and 6 tbsp of warm water. Let the mixture set for 5 minutes.
In a large bowl, cream butter and sugar together with a hand mixer, stand mixer, or whisk for about 30 seconds, until creamy and no clumps remain.
Next, add in your flax eggs and vanilla and mix for another 30 seconds until creamy.
Then, add in baking powder, baking soda, and salt and mix well.
Add in all the flour a bit at a time and mix well. When it becomes difficult to mix, use a spatula to mix in the flour to the dough.
The dough should be sticky but still be able to form a ball. Once your dough has this consistency, place the ball of dough on a floured countertop (make sure the counter has a good amount of flour sprinkled on it). Add more flour to the top of the dough and roll it out a bit with your hands to ensure the dough is not as sticky.
You can roll out our dough either with a rolling pin or your hands. Roll out dough to about ¼ inch thick and flour your cookie cutter before cutting your shape into the dough (this prevents sticking!) and cut your cookie shapes. Repeat for remaining dough.
Transfer cookies onto your parchment lined baking sheet and bake at 350ºF for 12-13 minutes, or until the edges are light golden brown.
Once cooked, remove from the oven and let cool for about 30 minutes or until cookies are cold before icing.
Ice your cookies once cooled and enjoy!