Preheat oven to 350°F.
Line a cookie sheet with parchment or a silicone baking mat. Set aside.
In a medium-size bowl, add the butter and sugar. Cream until they are well mixed. Do not over-mix.
Add the vanilla and chia egg. Mix well.
Add the baking powder and mix. Mix in the flour one cup at a time. Mix with your hands until a firm yet soft dough is formed.
Roll out half of the dough out on a prepared surface until it’s about 3/8″ thick.
Cut out shapes with a cookie cutter.
Place cookies on the prepared cookie sheet. Roll out and cut remaining dough.
Bake cookies for 6-8 minutes. They are done when the bottoms have slightly browned and cookies are white and soft to the touch (they harden when cooling). Do not over-bake. If you are using a silicone mat, it can take longer, up to 12 minutes. Set a timer to 8 minutes and check bottoms to see if done.
Let cookies cool on a baking rack. Once completely cool, ice and add decoration.