Mix 3 cups flour, 2 teaspoons baking powder, and 1 teaspoon salt together in a bowl. Stir in 1 cup white sugar, brown sugar, 1 cup melted butter, 2 eggs, and vanilla extract until batter is just combined. Pour batter into the prepared baking dish.

Preheat oven to 350°F (175 degrees C). Lightly grease a 9x12-inch baking dish.

Beat 1 cup white sugar and 1 cup melted butter together in a bowl until creamy. Stir in pumpkin puree, 1 cup flour, 2 eggs, 1 tablespoon cinnamon, pumpkin pie spice, nutmeg, 1 teaspoon baking powder, and 1 teaspoon salt until batter is smooth. Pour batter over the partially-baked bottom layer

Bake in the preheated oven until slightly done, 5 minutes.

Mix 1 tablespoon white sugar and 1 teaspoon cinnamon together in a small bowl; sprinkle over pumpkin layer.

Bake in the preheated oven until a knife inserted in the center of the cake comes out clean, about 35 minutes.