Preheat the oven to 350 degrees Fahrenheit.
In a large bowl, whisk together the pumpkin puree, brown sugar, white sugar, eggs, pumpkin pie spice, cinnamon, salt, vanilla bean paste, and heavy cream until completely smooth.
In a separate bowl, mix together the flour, oats, brown sugar, and salt.
Pour the melted butter over the dry ingredients and mix with a fork or your hands until a crumble forms. Leave some larger chunks; you don't want a smooth mixture.
Pour the pumpkin filling into a lightly greased 7x11-inch baking dish.
Evenly sprinkle the streusel crumble over the top.
Bake for 40–45 minutes, or until the pumpkin filling has mostly set. The center may still have a slight jiggle, similar to a traditional pumpkin pie, but should not be runny.
Allow to cool completely before serving. Refrigerate if desired and serve with whipped cream or vanilla ice cream.