Gather the ingredients for both the cake and frosting.
Preheat the oven to 350°F (175°C).
To make the cake: In a medium bowl, beat together the pumpkin puree, sugar, oil, and eggs with an electric mixer until well combined.
In a separate bowl, sift together the flour, cinnamon, baking powder, baking soda, and salt.
Add the sifted dry ingredients into the pumpkin mixture and stir until thoroughly combined.
Spread the batter evenly into an ungreased 10x15-inch jelly roll pan.
Bake in the preheated oven for 25 to 30 minutes, or until the cake bounces back when gently pressed. Remove from the oven and allow to cool.
While the cake is cooling, prepare the frosting: Beat the butter and cream cheese together until smooth. Stir in the vanilla extract. Gradually add the confectioners' sugar, beating until smooth and well combined.
Once the cake has cooled, spread the frosting evenly over the top. Cut the cake into 24 squares.
Enjoy!