Make the cookies. In a medium size bowl, sift together the plain flour, baking powder and cinnamon and set aside. Using a handheld or stand mixer with the paddle attachment fitted, beat dairy-free butter and caster sugar in a large bowl. Add vanilla, almond extract, coconut oil and milk and continue mixing on high for 2-3 minutes until fully combined.
Mix in sifted flour mixture slowly until the mixture just comes together.
Divide dough evenly into 2 parts and roll each out to 5m thickness onto lightly floured baking paper with a little more flour if the dough is too sticky. Cover with another sheet of baking paper and place into the fridge for at least 3 hours or overnight to chill. This step ensures the cookies hold their shape in the oven.
Preheat the oven to 180°C and line 2 baking sheets with baking paper. Remove the dough from the fridge and use a cookie cutter to make shapes, rolling out again until all the dough is used. Anytime you are not actively using the cookie dough, such as while waiting for a batch to cook, cover dough with baking paper and place back in the fridge. You want to always be working with cold dough.
Place cut out shapes onto the baking sheet and bake for 8 minutes or until cookies start to turn a light golden colour around the edges. They may still be a bit soft but will firm up as they cool. Let cool completely on a wire rack before icing.
Make the icing. In a small bowl, sift the icing sugar to ensure there are no lumps. Make a well in the centre of the icing sugar and add the vanilla and ½ a tablespoon of water. Using a metal spoon, stir the icing sugar from the edges into the centre until the icing starts to come together. Add in a little more water until the icing is smooth but still quite thick. If you add too much water, just add a little more icing sugar. Divide the icing into bowls (depending on how many colours you want to use) and tint the icing with a few drops of gel food colouring until it reaches your desired colour.
Decorate the cookies. Place the icing into a piping bag with a thin round tip and carefully pipe around the edges of the cookies to outline them. Once complete let dry for 30-60 minutes until the outlines have formed a crust. Squeeze remaining icing back into the bowl and add a small amount of water to thin out the mixture. Place icing back into the piping bag and fill in the outlines of the cookies. Set aside on a wire rack to dry for another hour or 2. Once the cookies have formed a crust, you can pipe on your designs.
The icing will crust after a couple of hours but they need to be left at least overnight to harden completely. The cookies themselves will remain soft and in the morning they will be fine to stack and store in an airtight container for up to 5 days.