Preheat oven to 350°F.
Lightly spray a 9x13 cake pan with cooking spray and then line the bottom with parchment paper. Lightly spray the parchment paper. Set aside.
In a small bowl combine the flour, cinnamon, baking powder, baking soda, sea salt, ginger, cloves and allspice. Whisk to combine.
In a stand mixer fitted with a paddle attachment, or with a hand mixer, on medium beat together the sugar and oil for 2-3 minutes. Slowly add in the eggs one at a time fully mixing in between additions. Next add in the pumpkin puree and vanilla. Mix together.
With the mixer on low add in the flour mixture and combine until you no longer see any dry bits.
Pour into the prepared pan and smooth out into an even layer so it reaches the corners. Bake for 10 minutes then rotate the cake 180 degrees and bake for another 10-15 minutes or until golden brown and bounces back when you press on it.
Remove from oven and let cool fully before frosting.
To make the frosting in a stand mixer fitted with a paddle attachment, cream together the cream cheese and butter for 1 minute on medium. Add in the vanilla and salt. Stop and start the machine occasionally to wipe down the sides of the bowl. Slowly add in the powdered sugar and mix until smooth, creamy and fluffy. If it looks too thick, add 1 tbsp. of milk at a time until it is a smooth, spreadable consistency.
Spread the frosting generously over the sheet cake and sprinkle with pumpkin seeds. Cut and serve. Will keep covered for 2-3 days.
Recipe Courtesy of Megan Mitchell