In a microwave-safe bowl, whisk cream and gelatin until all the gelatin is wet and the mixture looks slightly lumpy. Let mixture sit until it looks like loose cottage cheese, about 5 minutes.
Microwave gelatin mixture until the gelatin has melted, about 1 minute, whisking after 30 seconds. Whisk until smooth and syrupy and no lumps remain. (If you still see lumps, trying microwaving for 30 second increments.)
In a large microwave-safe bowl, whisk together pumpkin, sugar, maple syrup, ginger, salt, cinnamon, and nutmeg until combined. Microwave until heated to 110 degrees, about 2 minutes, stirring after 1 minute.
Immediately whisk in gelatin mixture until combined. Pour filling into crust. Gently shake pie filling so it spreads to the edges of the crust. Cool 10 minutes.
Spray a sheet of plastic wrap with nonstick spray and gently press on top of the filling. Refrigerate for at least 4 hours. Or, wrap in aluminum foil and freeze for up to 2 weeks (To serve, completely unwrap pie and thaw at room temperature for 5 hours).