Preheat & Prep the Pan: Preheat your oven to 350°F (175°C). Grease a standard 10x15-inch jelly roll baking sheet pan (or standard 9x13-inch pan for extra thick bars) with butter or cooking spray, and line with parchment paper for easy slicing.

Beat Wet Ingredients: In a large mixing bowl with an electric hand mixer (or stand mixer fitted with the paddle attachment), beat the eggs, granulated sugar, oil, and pumpkin puree together on medium speed for about 2 minutes until completely smooth, lightened, and emulsified.

Whisk Dry Ingredients: In a separate medium bowl, whisk together the flour, ground cinnamon, pumpkin pie spice, baking powder, baking soda, and kosher salt until evenly distributed.

Combine into Velvety Batter: Add the dry ingredient mixture to the wet pumpkin mixture along with vanilla extract. Beat on low speed just until combined and no flour streaks remain. Do not overmix.

Spread & Bake: Pour the smooth batter into the prepared baking pan, using an offset spatula to spread it evenly into all corners. Bake at 350°F (175°C) for 25 to 30 minutes, or until the center springs back when lightly pressed with a fingertip and a toothpick inserted into the center comes out clean. Transfer the pan to a wire cooling rack and let cool completely (about 1 to 1.5 hours).

Whip the Cream Cheese Frosting: While the bars cool, beat the softened cream cheese and softened butter together in a mixing bowl on medium-high speed for 2 to 3 minutes until pale, light, and creamy. Add vanilla extract and pinch of salt. Gradually beat in the powdered sugar, one cup at a time, on low speed. Add heavy cream and increase speed to high, beating for 1 to 2 minutes until silky, thick, and fluffy.

Frost, Slice & Serve: Once the pumpkin bars are completely cool, dollop the cream cheese frosting across the surface and spread evenly with an offset spatula, creating decorative rustic swirls. Lightly dust with cinnamon and scatter chopped toasted pecans if desired. Slice into 24 generous bars and enjoy!