Preheat the oven to 350 degrees. Use the convection bake setting if you have it.
Add the softened butter, granulated sugar and brown sugar to a large mixing bowl and cream them on high using a hand or stand mixer. Do this for about a minute, then scrape down the bowl once complete.
Add the vanilla, egg, ¼ cup reduced apple cider, cinnamon, nutmeg, allspice, salt and baking soda. Mix until well-combined. Scrape down the bowl with a silicone spatula.
Add the flour in 2-3 portions and mix well.
Add the oats in 2-3 portions and mix well. Scrape down the bowl once complete.
Use a cookie scoop to spoon the dough on to a lined cookie sheet. Leave 2 inches in between each cookie. (spraying the cookie sheet with baking or cooking spray is OK too)
Bake the cookies for 15-18 minutes or until the edges and bottom begin to brown.
Remove them from the oven and allow them to cool to room temperature before adding the icing.