Heat Oven. Preheat oven to 350 degrees F. Place the chocolate pie crust on a rimmed baking sheet.
Make Filling. Whisk together pumpkin puree, eggs, evaporated milk, sugar, spice, and salt. Mix until smooth, about one minute.
Bake Pie. Bake until center is set but still jiggles slightly, about 45 minutes.
Top and Toast Marshmallows. Allow pie to cool slightly, about 20 minutes. (Pie may also be chilled overnight.) Arrange marshmallows on top of pie, taking care to cover the entire top, so the pumpkin filling doesn't burn.
Turn broiler to high. Place pie under broiler until marshmallows are golden brown and puffy, about 3 minutes.
Pour the filling into small oven-safe custard cups.
Place the cups on a baking sheet and bake until set, about 30 minutes.
Top the cups with marshmallows and toast as directed with the pie.