Preheat the oven to 350 degrees F (180 degrees C). Grease the bottom of a 9x9 square baking dish or loaf pan.
In the bowl of an electric mixer with the paddle attachment (or hand mixer), cream the Butter (1 stick), Brown Sugar (3/4 cup) and Granulated Sugar (3/4 cup) until light and fluffy.
Add the Light Sour Cream (1/2 cup), Pumpkin Purée (1 can), Vanilla Extract (2 teaspoon), Egg (2) and mix until combined.
Sift together the All-Purpose Flour (2 1/4 cup), Baking Soda (1 1/2 teaspoon), Baking Powder (1 1/2 teaspoon), and Kosher Salt (1 pinch). With the mixer on low, slowly add in the flour mix until combined. Transfer to baking dish.
Combine Old Fashioned Rolled Oats (1/2 cup), All-Purpose Flour (1 tablespoon), Toffee Bits (1/4 cup), Ground Cinnamon (1/2 teaspoon), Brown Sugar (1 1/2 tablespoon), and Butter (1 1/2 tablespoon) in a bowl and mix until the butter is evenly distributed.
The streusel will be crumbly and slightly "wet" from the butter. Crumble on top of the pumpkin bread.
Bake for 1 hour or until the bread passes the tooth pick tests or tooth pick comes out clean.