Preheat your oven to 350 degrees. Prepare a 13x9 or similar-sized baking dish or casserole dish with some non-stick cooking spray. Set aside.
In a large bowl, combine the canned pumpkin puree, sugar, evaporated milk, eggs, vanilla, pumpkin spice and salt. Whisk to combine, or use a hand mixer. Pour this pumpkin mixture into the prepared baking dish from the mixing bowl and spread evenly.
In another medium-sized bowl, combine the dry ingredients. This includes crushed cookies, oats, brown sugar, baking soda and baking powder. Stir well to combine. Cut in the butter using two forks or a dough cutter. The mixture should be crumbly.
Sprinkle the topping mixture evenly over the top of the pumpkin layer.
Bake in the oven for approximately 35-45 minutes or until the topping is set and the filling is bubbling. The internal temperature of the mixture should be 175 degrees if you have a thermometer handy. A little wiggle in the center is okay - the filling will solidify once cooled.
Allow to cool slightly before serving. It can be served warm with ice cream or whipped cream. Also delicious served chilled.
Notes
Storage: Store your pumpkin crisp in an airtight container for up to 3 days.