Preheat your oven to 350°F (175°C). In a mixing bowl, combine crushed gingersnap cookies with melted butter until well blended. Press this mixture into a 9-inch pie pan. Bake for about 10 minutes or until golden and fragrant, then let cool.

In a large mixing bowl, whisk together the pumpkin puree, brown sugar, cinnamon, and nutmeg until smooth. Add in the eggs, vanilla extract, and heavy cream, mixing thoroughly.

Pour the filling into the cooled crust and bake for 45–50 minutes or until set but slightly jiggly in the center. Let cool on a wire rack for at least 1 hour.

Turn the broiler on high. In a small bowl, mix mini marshmallows with melted butter and cinnamon sugar. Evenly distribute over the pie.

Place the pie under the broiler for 1–2 minutes, watching closely until golden brown. Remove when toasted.

Let cool for a few minutes before slicing. Serve warm or at room temperature.