Heat the oven to 350°F (175°C) and lightly grease a 13 x 9-inch baking pan. Set the pan aside while preparing the cake batter.

Add the yellow cake mix, solid-pack pumpkin puree, vegetable oil, water, eggs, cinnamon, and nutmeg to a large bowl. Beat with an electric mixer on medium speed for 1–2 minutes, just until the batter is smooth and evenly blended.

Spread the pumpkin batter evenly in the prepared pan. Use a spatula to reach the corners and create an even layer.

Stir together the firmly packed brown sugar, melted unsalted butter, and chopped pecans in a separate bowl. Mix until the pecans are coated and the topping looks thick and glossy.

Sprinkle the praline mixture evenly over the cake batter, distributing the pecans from edge to edge. Avoid piling the mixture in only the center so every slice receives some topping.

Bake for 35–40 minutes, or until the center is set and a wooden pick inserted into the cake, rather than only the topping, comes out clean or with a few moist crumbs. If the topping browns before the center is done, continue checking the cake carefully near the end of the baking time.

Cool the cake on a wire rack for 20–30 minutes before slicing. The praline topping firms as it cools, making the pieces easier to cut and helping the buttery layer keep its crisp-chewy texture.