Add carrots, parsnip, zucchini, apple and walnuts. Mix until combined.
Spread batter evenly into pan.
Bake on middle rack in oven until cake is uniformly brown, firm to touch and toothpick/knife comes out clean when inserted into middle of cake (about 45-55 minutes).
Let cool for 15 minutes, then take out of cake pan and place on a cooling rack until completely cool (at least 1 hour).
Make frosting:
Whip together butter, cream cheese and cider for about 3 minutes (note: make sure your butter and cream cheese are soft first or your frosting will be lumpy- gross!).
Slowly add powdered sugar and cinnamon, beat until blended.
Add more powdered sugar and cinnamon as needed.
Frost cooled cake.
Recipe by Homegrown Friends at https://homegrownfriends.com/home/fall-harvest-cake-cinnamon-cider-frosting/