Preheat oven to 350 degrees F (175 degrees C). Line two 9-in (23cm) round cake pans with parchment paper and coat with cooking spray.
In a medium bowl, whisk together flour, baking powder, salt and cinnamon. Set aside.
In a mixing bowl with paddle attachment, beat the eggs, vegetable oil, sugar and vanilla extract until combined, about 2 minutes. Add the flour mixture and mix until mostly combined with some dry flour visible. Add shredded carrots and pecans. With rubber spatula, mix the batter until everything is just combined.
Divide the batter into the prepared pans. Bake for 23-25 minutes, or until the inserted toothpick comes out clean. Transfer to wire rack to cool for 5 minutes. Then remove the cakes from the pan and cool completely.
Meanwhile, make the frosting. In mixing bowl with whisk attachment, beat the cream cheese and butter until fluffy. Add powdered sugar, heavy cream and vanilla extract. Beat the mixture on low for a minute, and then slowly increase the speed to medium high. Beat the frosting until smooth and fluffy, about 3 minutes.
To assemble the cake, spread half of the frosting on one cake. Then place the second cake on top and spread the remaining frosting. Decorate with some pecan pieces, if desired.