In the bowl of a stand mixer, beat the softened butter, shortening and cream cheese until super pale and fluffy, about 5-6 minutes.
Scrape down the sides and bottom of the bowl. Add the powdered sugar, one cup at a time and beat on low speed after each cup until combined.
Once combined add vanilla and salt and continue to beat until combined and smooth.
Increase speed to medium-high and beat for about 5-7 minutes, or until frosting is light and fluffy.
FOR THE CARROT TOPPING:
Line a baking sheet with wax paper. Set aside.
Add ½ cup of the cream cheese frosting to 2 separate bowls. Tint one half orange and the other green.
Spoon the orange frosting into a disposable piping bag fitted with a small round tip. Put the green frosting into a piping bag fitted with a small leaf tip. Set aside.
With the orange frosting, pipe a short line onto the baking sheet, release pressure on the piping bag, then drag the piping bag out without squeezing so you get a pointy tip. Repeat a few more times, piping out as many as you can. It’s good to have extra in case you mess up. Make sure you leave enough room at the top of the carrot for the leaf.
Use the green frosting with the leaf tip to pipe small leaves onto the top of each carrot. Transfer baking sheet to the freezer. Meanwhile, assemble the cake.
ASSEMBLY:
Place one cake layer on a serving plate or cake board on a turntable. Spread about 1 cup of frosting on top using an offset spatula.
Repeat with remaining layers and place final layer top side down.
Frost entire cake in a thin layer of the cream cheese frosting to seal the crumbs.
Frost with another thick layer of frosting. Use a bench scraper or a long straight spatula to smooth out the sides and top.
Pour chopped pecans into a large bowl and place turntable into a large rectangular cake pan to catch excess pecans.
Take a handful of pecans and press up the sides of the cake. Repeat until entire cake is covered. You can go back and fill in any bald spaces.
Transfer remaining frosting to a piping bag fitted with a large star tip, I used Wilton 1M. Pipe a reverse shell border on top of the cake. Sprinkle extra chopped pecans around the edges.
Remove frosting carrots from the freezer and use an offset spatula or butter knife to gently slide underneath the carrots to loosen. Pick up the carrots and place on top of the cake in the position you prefer. Slice, serve and enjoy!
