1-Preheat oven to 375°F: Preheat oven to 375°F. Butter a 12-inch cast iron skillet or a 9×9 baking dish. Set aside.
2-In a large bowl, whisk together pumpkin,: In a large bowl, whisk together pumpkin, sugar, eggs, pumpkin pie spice, salt, and vanilla extract. Whisk in heavy cream until smooth. Pour into prepared skillet and set aside.
3-In a medium bowl, whisk together flour,: In a medium bowl, whisk together flour, sugar, cinnamon, and salt. Add melted butter in three pours, stirring with a fork (or pressing together with your fingers) until crumbly. Spread cinnamon streusel topping on top of pumpkin pie mixture in an even layer.
4-Bake until filling is set and top: Bake until filling is set and top is golden brown, 40 to 45 minutes. If the crumb topping happens to brown too quickly, you can lightly cover the top with foil to prevent it from browning any more.
5-Let cool for 10 minutes, so the: Let cool for 10 minutes, so the custard filling can firm up. Then serve warm topped with ice cream or whipped cream. My personal favorite combination is to serve this pumpkin crisp with cinnamon ice cream if you can find it!