Preheat oven to 350F. In an electric mixing bowl, beat your softened butte and brown sugar together for 2-3 minutes.
Then, add in vanilla and flax egg. In a separate bowl, combine flour, salt and baking powder. Then, add dry ingredients to wet.
Once the batter is well incorporated, roll dough into balls and place on a baking sheet lined with parchment paper Press down slightly with your fingers to flatten the tops and then bake for 10 minutes.
Once the cookies are out of the oven, start your frosting. Beat your butter until fluffy. Then add in your powdered sugar. Add in maple syrup.
Once the cookies are completely cool, frost them!