Make the Pie Crust first. It needs to chill for 1 to 2 hours before being rolled out. So plan ahead to allow for this chilling time. See the Pie Crust recipe below, in Recipe Notes.
For Pie Crust recipe, see Recipe Notes (MAKE IT FIRST). Then: Preheat oven to 350 degrees Fahrenheit. Roll out the dough between two layers of parchment paper to a 13-inch round that's about 1/4" thin or slightly thinner in the middle. Transfer the dough into a 9" glass pie plate. Fold the edges of the dough under and crimp decoratively. Place in the freezer for 15 minutes.
While the pie crust is in the freezer, melt the chocolate gently: over a water bath, over very low heat in a heavy bottomed small pan, or in the microwave. (Do not let any water drops or steam get into the chocolate. Be sure to use a dry container or pan.) Keep warm over lowest, gentle heat while you prepare the pie filling.
For the filling: In a medium-size bowl, use a blender or hand held beaters on low speed to whisk the eggs, sweetener, cornstarch, cinnamon, cloves and sea salt until smooth. Blend in the pumpkin puree. Add the cream and whisk again briefly.
Carefully crimp 4 strips of tin foil around the edges of the pie crust. Prick the crust with a fork all over. Bake pie crust for 10 minutes.
Transfer 1 cup of the pie filling to a smaller bowl and, using one beater of an electric mixer, blend in the melted chocolate.
Pour the remaining pumpkin filling into the pre-baked crust. Dollop the chocolate filling on top, and swirl it in with a butter knife (see how-to here). Bake the pie for about 45 minutes, until the custard is set. Carefully remove tin foil strips. Cool the pie on a wire rack completely before serving. Serve with optional, sweetened whipped cream.