Toast the pecan and spices (ginger, cinnamon, nutmeg) in a small nonstick skillet over medium heat until lightly toasted and fragrant, roughly 5 minutes. Don’t overdo! It’s easy to burn pecans. Transfer to plate to stop the cooking and let cool.
Arrange half the Biscoff cookies or gingersnaps to cover the bottom of a 9”x13” baking dish (a little overlapping is ok).
Scoop the ice cream into a large bowl and soften by mixing and mashing with a wooden spoon. When the ice cream is soft enough to stir (but not melting!) fold in the pumpkin, sugar, salt, and the cooled pecans/spices until combined.
Spoon half the ice cream mixture over the cookies in the baking dish and gently smooth the surface. Add the remaining cookies to the top of the ice cream and then finally, top with the rest of the ice cream mixture. Cover the top with plastic wrap (two layers is best especially if preparing in advance) and then freeze until firm, about 6 hours.
To serve, cut into squares and top with whipped cream. If you are feeling fancy you could toast additional pecans and top with pecans and a sprinkle of cinnamon too!