Preheat the oven to 350 and spread the pecans in an even layer on a cookie sheet; toast them in the oven for about 8 minutes.
Grease (or line with parchment) a 9 x 13" pan (or two 9x5 loaf pans) and set aside.
In a large stainless steel bowl, whisk together the oil and the sugar until combined.
Add eggs, pumpkin and water and whisk again.
Whisk in flour, baking soda, spices and salt; stir to just combine.
Spread into prepared pan and set aside.
In a small bowl, mix together the topping ingredients.
Crumble the topping evenly over the batter, sprinkle with the pepitas if using and bake for about 50-60 minutes (or until the middle springs bake and feels solid).
Cut into squares and serve warm with some cold vanilla ice cream!