Preheat oven to 350.
Whisk together flour, cinnamon, baking powder, baking soda and salt. Set aside.
Beat eggs, sugar, oil and pumpkin in a large bowl until well blended.
Slowly add to dry ingredients to wet ingredients, mixing well.
Pour into ungreased 9x13" baking pan.
Bake for 25-30 minutes or until set.
Beat cream cheese, butter and vanilla until well blended.
Slowly beat in powdered sugar.
Spread frosting over cake and refrigerate until ready to serve.