Preheat the oven to 350°F. Set the oven to 350°F. Whisk the pumpkin puree and evaporated milk with the eggs for 45 to 60 seconds. Add the dark brown sugar and pumpkin pie spice with the fine sea salt and vanilla. Keep whisking until the mixture looks smooth and the sugar stops sitting in streaks. Scrape the mixture down once halfway through. Stop after 90 seconds so you don't whip in excess air. Next, look for a glossy deep-orange custard with no visible egg threads. It should smell clearly of cinnamon and pumpkin spice. If dry sugar still clings in patches, whisk another 10 seconds. Go too long and the extra air can make the filling puff unevenly before sinking. This smooth base helps Dump Cake Pumpkin Fall Desserts set into a creamy layer instead of separating. Mix only until smooth because over-aeration creates an uneven custard structure.

Pour the pumpkin mixture into a 9x13-inch baking dish and let it settle for 2 minutes at room temperature. Tilt the dish gently once toward each corner so the custard reaches an even depth. Don't stir after pouring. The surface should level itself while a few tiny bubbles rise and break. Keep the oven at 350°F while you build the topping over this base. Then check the depth from corner to corner. The orange layer should look even but not perfectly flat. If one side is noticeably deeper, tilt the dish for 3 to 5 seconds and stop. Leave large bubbles and the cake can form hollow spots under the topping. Dump Cake Pumpkin Fall Desserts bakes most evenly when this custard layer has the same thickness across the pan. Even depth matters because the eggs need equal heat to set at the same rate.

Sprinkle the dry yellow cake mix over the pumpkin layer in an even blanket. Work from the outer edges toward the center for 60 to 90 seconds. Next, scatter the chopped pecans over the dry mix and leave a few bare patches. Don't press or stir the layers together. The oven should still hold at 350°F while the topping stays visibly dry and loose. You should see pale yellow crumbs with irregular tan pecan pieces across the entire dish. Some orange pumpkin may peek through at the edges, and that's fine. If thick piles of cake mix remain, they can bake into dusty pockets. (I once left a mound in one corner, it stayed floury after baking.) Keep the layer loose so melted butter can travel through it. Loose layering matters because dry mix needs direct contact with butter and steam.

Arrange the chilled unsalted butter slices across the cake-mix layer with small gaps between them. Bake at 350°F for 50 to 55 minutes. At minute 35, rotate the dish 180 degrees if your oven browns unevenly. Don't stir the topping while it bakes. The butter should melt through the dry mix while the pumpkin layer firms underneath and the pecans toast across the surface. By minute 50, the top should show deep golden patches and darker toasted pecans. The edges will bubble slowly and smell like browned butter with warm spice. A gentle shake should leave only a slight wobble at the center. Pull it before the topping turns dark brown. Go past 60 minutes and the custard can tighten while the pecans taste bitter. Dump Cake Pumpkin Fall Desserts needs that narrow golden window. Bake at 350°F because moderate heat sets the custard before the topping burns.

Rest the baked cake for 20 minutes at room temperature before serving. The center will continue setting as the temperature drops. Scoop one portion onto a white plate and add 1/4 cup vanilla bean ice cream on top. Let the ice cream sit for 60 seconds so the bottom softens against the warm crumble. Don't serve immediately from the oven because the pumpkin layer will be too loose. The finished portion should show a soft orange custard base and a rough golden pecan crust. Small crumbs should fall naturally around the scoop. The ice cream should soften at the edges but still hold its shape. If the serving slumps into a puddle, the cake needed more resting time. Wait the full 20 minutes so the egg-set custard firms enough to scoop cleanly. Resting gives the custard proteins time to finish setting without further oven heat.