Whisk 1 3/4 cups pumpkin puree with 4 large eggs, 1 cup vegetable oil and 1 1/2 cups granulated sugar in a bowl for 2 to 3 minutes. Add 2 cups all-purpose flour, 2 teaspoons cinnamon, 1 teaspoon baking powder, 1 teaspoon baking soda, 1/2 teaspoon salt and 1 teaspoon vanilla extract, then fold with a rubber spatula using slow circles for 60 seconds. (I tried adding extra spice first and the pumpkin taste disappeared, so this ratio stayed.) The batter becomes thick and orange with a smooth surface. You'll smell the cinnamon right away. Skip the full mix and flour pockets stay hidden. Mix for 60 seconds after combining because even flour distribution keeps the crumb tender.

Spread the batter into a greased 9x13 inch baking pan and bake at 350°F for 25 to 30 minutes. Smooth the top with a spatula and rotate the pan halfway through the baking time for even color. The center should rise slightly and the edges should become golden. The surface changes from glossy orange batter to a soft golden top with a gentle pumpkin smell. A toothpick should come out with a few moist crumbs. Miss the timing and the middle can stay wet. Bake at 350°F for 30 minutes because steady heat sets the cake structure without drying it.

Beat 16 ounces cream cheese with 1 cup powdered sugar and 1 teaspoon vanilla extract for 2 to 3 minutes at medium speed until smooth. Scrape the bowl halfway and mix again for 30 seconds until the frosting looks thick and spreadable. The frosting turns bright white with a creamy texture. You'll see soft peaks form. Overmix past 3 minutes and the topping may become loose. Beat for 3 minutes because the air creates a lighter frosting texture.

Spread the frosting over the cooled pumpkin cake layer in an even but slightly rustic layer. Chill the frosted bars at 40°F for 60 minutes before slicing so the topping firms up. Use gentle sweeping motions to avoid tearing the cake. The white frosting sits over the orange base with natural waves and small imperfections. You'll notice a creamy smell from the cheese. Cut too early and the layers can slide. Chill for 60 minutes because the frosting needs time to hold its shape.

Cut the chilled dessert into 12 uneven squares and transfer single portions to a plate. Serve at 40°F to 45°F after resting for 5 minutes outside the fridge. Use a clean knife between cuts for sharper layers. The slices show a moist orange crumb under the creamy white frosting. The edges look slightly darker and homemade. Cutting too quickly can smear the frosting. Rest 5 minutes before serving because the cake softens while keeping the frosting stable.