Preheat oven to 350 degrees. Lightly grease an 8" square baking dish and set aside.
In medium bowl, whisk together flours, baking powder, cinnamon, baking soda, and salt.
In another bowl, whisk eggs for 30 seconds. Add brown sugar, pumpkin, oil, and orange zest, and mix until very smooth.
Add flour mixture to egg mixture and stir just until moist. Stir in carrots.
Scrape batter into prepared baking dish and smooth top, then bake for 23-25 minutes, until toothpick inserted in centre comes out clean.
Set on wire rack to cool before icing.
For icing: With electric mixer, beat together cream cheese and butter. Add icing sugar, vanilla, and milk and mix until smooth and creamy. Store cakes iced with cream cheese icing in fridge.
Notes
Options: 1) Add ½ cup golden raisins to batter 2) Top with chopped pecans or walnuts
Recipe by Hidden Ponies at https://hiddenponies.com/2013/10/saturday-sweets-pumpkin-carrot-cake-with-cream-cheese-icing/