Preheat oven to 350 degrees. Grease a 15x10 inch pan (a large rimmed cookie sheet for me) and set aside.
Beat together sugar, pumpkin, oil, and eggs. In a separate bowl, combine flour, cinnamon, baking soda, salt, and nutmeg. Gradually add dry ingredients to the pumpkin mixture and mix well.
Pour into prepared pan and spread evenly. Bake for 20-25 minutes, until toothpick inserted in center comes out clean. Remove from oven and cool on a wire rack.
Prepare frosting: beat cream cheese, butter, and vanilla until smooth. Gradually add powdered sugar until smooth and desired consistency is reached. Add in a couple teaspoons of milk to thin out frosting. Spread on top of cooled cake then sprinkle with cinnamon and chopped pecans if desired.
Pumpkin Sheet Cake - Ideas for the Home by Kenarry®