Place the apple cider in a small saucepan and bring to a simmer over a medium heat. Simmer, stirring now and then, for around 10 - 15 minutes until the volume has reduced to a quarter of the original (for 1 recipe volume, you want 1 cup, 240ml to reduce to ¼ cup, 60ml). Leave to cool.
Place the flour, cinnamon, nutmeg, cloves, salt and baking powder in a bowl and whisk gently to mix so the additions are well distributed.
Cream the butter, regular and brown sugars with a stand mixer, or use a handheld mixer until well mixed and gently glossy. Add in the egg, reduced cider and vanilla and mix in.
Add the flour mixture - you can add part at a time if easier - and mix together so the dough comes together, but be careful not to overmix.
Refrigerate the mixture for around 30 minutes, or longer if it suits you better, to help it firm up slightly.
Shortly before ready to bake, preheat oven to 350F/180C. Line a couple of baking sheets/trays with silicone mats or parchment paper. Mix together the sugar and cinnamon for rolling in a small, shallow bowl and mix so the cinnamon is evenly distributed.
After chilling, use a small cookie scoop then roll balls of dough briefly in your hands to smooth off (you can also use a tablespoon measure if you don't have a scoop). Roll each ball in the cinnamon sugar then place on the lined baking sheet with a little space between them. Repeat with the rest of the mixture.
Bake the cookies for around 10-12 minutes until the cookies look dry and are just about starting to brown on the base and edges. Allow to cool a minute before transferring to a cooling rack to cool completely.
Once cookies are completely cool, combine the confectioner's/icing sugar and apple cider in a bowl and mix until smooth. If it is a little too thick to drizzle, add a drop or two more apple cider, but only add a very small amount at a time as it can easily become too liquid. Drizzle the icing over the cooled cookies with a small spoon (or you can use a piping bag to be more precise), making a few lines over each cookie. Leave to firm up before serving/storing.