Before you start, line an 8x5 loaf pan with parchment paper and preheat the oven to 350 F/180 C.
In a medium bowl, combine the flour, brown sugar, cold butter, cinnamon, and pecans until the mixture is crumbly. Set aside until ready to use.
In a large mixing bowl, whisk together the melted butter, oil, sugar, and brown sugar.
Then whisk in the eggs, vanilla, and pumpkin.
Whisk in the flour, baking powder, baking soda, salt, and cinnamon. Pour the pumpkin batter evenly into the prepared pan, then spread the streusel topping over the top of the batter.
Bake for 35-40 minutes, or until the pecans on top are brown. Then remove the loaf from the oven and loosely cover the top with aluminum foil. This will keep the pecans from burning. If you notice they are browning sooner, cover it as soon as possible. Continue baking for another 11-16 minutes, or until a toothpick inserted into the center is covered in a few moist crumbs. Let the pan cool completely on a wire rack then slice and enjoy!
Store leftovers wrapped in plastic wrap in an airtight container in the fridge for up to 5 days. I recommend slicing it only when you are ready to eat or serve it otherwise it may dry out. You can also freeze the loaf whole or in slices wrapped in plastic wrap for up to 1 month.