Preheat the oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan.

In a large mixing bowl, combine granulated sugar, brown sugar, pumpkin puree, and vegetable oil. Mix until smooth.

Add eggs one at a time, mixing well after each addition.

In another bowl, whisk together flour, baking powder, baking soda, cinnamon, nutmeg, and salt.

Gradually add the dry ingredients to the wet mixture, mixing until just combined.

Pour the batter into the prepared baking pan and smooth the top.

Bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean.

Remove the cake from the oven and let it cool for 10 minutes.

Using the handle of a wooden spoon, poke holes all over the top of the cake.

Pour the caramel sauce over the warm cake, allowing it to seep into the holes.

Let the cake cool completely before adding the topping.

Spread whipped cream over the top of the cooled cake.

Sprinkle with chopped pecans if desired.

Slice and serve chilled or at room temperature.