Preheat oven to 350 degrees F. In a large bowl, whisk together sugar, cornmeal, cocoa and salt. Add eggs, melted butter, corn syrup and vanilla; mix well. Pour into unbaked pie crust.
Bake for 45-50 minutes, or until mostly set – there will still be a little bit of jiggle in the center when you shake the pie. Allow the pie to cool completely before slicing (it will continue to set as it cools). If the pie is still a bit too soft after cooling, chill it in the refrigerator for a few hours to firm it up.
Notes
Make sure that the melted butter is cooled slightly before adding it to the filling -- or you might end up with scrambled eggs!
Extreme temperature changes can cause the pie filling to crack on top, so allow the pie to cool gradually at room temperature. Do not place a hot pie in a cold refrigerator.
Allow plenty of time for the pie to chill. It will continue to firm up and set as it rests, so it's best to make this pie the day before you plan to enjoy it. If you try to slice the pie while it's still hot, the filling will be runny.
Before serving, allow a refrigerated pie to come to room temperature on the counter for about 30 minutes. If you'd like warm slices of pie, reheat in the microwave for about 15 seconds. It will taste gooey, fudgy and like it's fresh from the oven! Just don't warm it for too long or it will turn into a melted mess.
Garnish with a dollop of whipped cream. Fresh berries, a sprig of mint, a dusting of powdered sugar, or a drizzle of caramel sauce would also be delicious!