Pumpkin Cake for a Crowd

For the Pumpkin Cake:
Preheat the oven to 350 degrees (F). Line a 9x13-inch metal baking pan with parchment paper, allowing two of the sides to overlap.
Spray the parchment paper, and any exposed pan, with nonstick baking spray. Set aside. (Note: if you use a glass or ceramic baking pan/dish, you may need to increase the bake time). 
In a large bowl, whisk the flour, all of the spices, the baking powder, and baking soda together until well combined. Set aside. 
In a separate large bowl, whisk the eggs for about 30 seconds, or until well combined. Add in the oil, sour cream, orange juice, molasses, vanilla, brown sugar, and pumpkin and beat until very smooth.
Using a rubber spatula, fold in half of the flour mixture, stirring just until smooth and completely combined. Fold in the remaining flour mixture, again mixing just until combined. Do not over mix. 
Scrape the batter into the prepared pan. Bake for 30 to 35 minutes, or until a toothpick inserted in the center of the cake comes out clean. 
Place the pan on a cooling rack and cool completely before removing the cake from the pan.  
Once cool, spread cream cheese frosting on top, slice, and serve!
For the Cream Cheese Frosting:
In the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl using a handheld electric mixer, beat the cream cheese and butter on medium-speed until completely smooth. 
Reduce the speed to low and gradually add in the confectioners' sugar, beating until all of the sugar is completely combined.
Add in the vanilla, salt milk, and cinnamon (if using) and beat smooth. Once all of the ingredients have been incorporated, increase the speed to medium-high and beat for a minute, or until very fluffy. 
Spread the frosting on top of the cake. Slice and serve!