Preheat the oven to 180°C / 350F. Grease a 6-hole donut pan and set aside.
In a large bowl, whisk together the milk, buttery spread, vanilla extract and brown sugar until well combined.
Add the flour, baking powder, salt and cinnamon. Whisk until just combined.
Evenly spoon or pipe the mixture into the donut pan. Give the pan a good shake and tap to even out the batter before placing in the oven.
Bake for 12 mins or until cooked through when tested with a skewer.
Cool for 10-15 minutes before carefully removing the doughnuts from the pan (if you gently twist them they pop out easily).
In the meantime, sift the icing sugar into a bowl and add in the milk, buttery spread and vanilla extract. Whisk until smooth. If it’s too runny, sift in some more icing or if it’s too thick, add 1-2 extra tsp of milk.
Divide evenly into 3 small bowls. Add the flavour add-ins (matcha, cocoa powder and freeze dried berry powder) into each bowl and whisk until well combined.
Dip each donut into the icing and transfer to a wire rack for any excess to drip off. Add on toppings to decorate and enjoy. Store any leftovers in an air-tight container at room temperature for up to 3 days or in the fridge for up to 1 week.