Cream butter and brown sugar together until well incorporated, about 1 minute.
Add egg and molasses, mix until well combined.
Add the orange zest, maple extract, and vanilla extract. Mix.
Add dry ingredients, mix until combined. The texture of the dough should be firm and very slightly sticky. Add more flour if needed.
Roll out dough to about 1/8 inch thick, or your desired thickness. Cut out into desired shapes.
Place on lined cookie sheet, leaving 1/2-1 inch between cookies. Place sheet tray with cut-out cookies in the refrigerator for 5 minutes.
Bake for 9-11 minutes, until the edges and the tops are set.
Let cool on the sheet tray 5 minutes. Remove from sheet tray and cool completely before icing.
For the Icing
Combine powdered sugar, vanilla and half of the milk.
Gradually drizzle in the milk while mixing until the icing is soft but not runny. A peak should slowly fall back onto itself when a whisk is pulled out.