Combine the crushed Biscoff cookies, butter, brown sugar, and salt in a large bowl. Mix well until the cookie crumbs clump together.
Divide the crumb mixture among six Mason jars or individual serving dishes and press firmly to create a crust in each jar. Freeze the crusts while you prepare the topping.
Use a hand mixer or stand mixer to whip the cream to stiff peaks in a large bowl.
In a separate large bowl, beat the cream cheese and powdered sugar until light and fluffy, about 1 minute. Mix in the pumpkin puree, pumpkin pie spice, and a pinch of salt.
Working in two batches, gently fold the whipped cream into the cream cheese mixture.
Divide the topping among the chilled crusts, cover, and refrigerate overnight to allow the filling to set.