Preheat oven to 350°F. Place a rack in the lower-middle position.
Set the unbaked pie crust on a rimmed baking sheet for easy handling.
Whisk sugar, cocoa, cornmeal, and salt in a large bowl until no cocoa lumps remain.
Beat in the eggs one at a time until the mixture looks thick and glossy.
Slowly stream in the melted butter while whisking until fully combined.
Whisk in milk, vanilla, and vinegar until the filling is smooth and pourable.
Pour the filling into the crust. Tap the pan gently to release bubbles.
Bake 45–55 minutes, until edges are set and the center has a slight jiggle. Shield the crust edges with foil if browning too quickly.
Cool on a rack until fully set, about 2 hours. Slice and serve at room temperature or chilled.
Notes
Swap 1/4 cup of the sugar for light brown sugar for a hint of molasses depth. Serve with lightly sweetened whipped cream or a sprinkle of flaky sea salt. Store covered in the refrigerator for up to 4 days; enjoy leftovers cold or at room temperature.This recipe is an original creation inspired by classic Easy Chocolate Chess Pie Recipe flavors. All ingredient ratios and instructions are independently developed.