Preheat your oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish. In a large bowl, mix all of the pumpkin pie layer ingredients until smooth.
Pour the mixture into the prepared baking dish.
In a medium bowl, combine all the topping ingredients. Use a fork to work the butter into the mixture until it becomes crumbly. Sprinkle this topping evenly over the pumpkin pie layer.
Place the baking dish in the oven and bake for 40–45 minutes, until the top is golden and the filling is set.
Serve warm on its own, or add a scoop of vanilla ice cream for an extra delicious treat.