Preheat the oven to 170°c. Line your cupcake tin with patty pans.
Melt the butter, sugar and maple syrup in a pan over a gentle heat, then allow it to cool slightly.
While you are waiting, grate the parsnips and the apple.
Sift the flour, baking powder, baking soda, salt and cinnamon into a bowl and set aside.
Once the maple syrup mix has cooled to room temperature, whisk the eggs into this mixture, then stir in the sifted dry ingredients. Mix well.
Fold in the grated parsnip and apple (and nuts if you wish).
Fill the patty pans to 2/3 full. Bake for 18-20 mins until a skewer inserted into the cupcake comes out clean.
Cool the cakes slightly in the tin before turning out onto wire racks to cool completely.
For the frosting
Beat the butter on high until light and fluffy.
Add the maple syrup and salt and mix to combine.
Add one cup of icing sugar and beat well.
Add the second cup, a little at a time, until the desired consistency is reached.
If you have a food processor, use it to grate the parsnip and apple. Otherwise, you might need an extra parsnip as some will come off in chunks when you are using a hand grater (and we don't want chunks in the cupcakes).