Preheat oven to 400F.
Before unrolling the pie crust, let it stand at room temperature 10 to 15 minutes according to the package directions. (This is a good time to pit the cherries!)
While the pie crust rests on the counter, wash the cherries and pat them dry with a paper towel.
Using an olive and cherry pitter, remove the pits from all the cherries. I like to pit them in a sink or a deep bowl this way because as you press down on the cherry pitter, it tends to splatter a little. The Oxo cherry pitteris my favorite because it has a little splatter guard built in which reduces the amount of red juice that splatters.
Toss the pitted, whole cherries together with the lemon juice in a large bowl. Combine 1 tablespoon sugar and cornstarch in atiny bowl. Sprinkle this mixture over the cherries and gently stir just until coated. Gently stir in half of the chopped chocolate.
Back to the pie crust: Gently unroll the crust and use a rolling pin or a glass with straight sides to roll out any creases. Fold the crust in half and transfer it to a piece of parchment paper on a baking sheet. Unfold the piecrust. Folding it in half keeps it from stretching while transferring.
Pour out the coated cherries onto the center of the crust, leaving about 2 inches from the edges. Be sure the crust is already on the parchment paper on a baking sheet.
Carefully, lift a small section (about 3 inches wide) of the outer edge of the pie crust and lay it toward the cherries, leaving most of the center uncovered. Lift another small section, slightly overlapping the first section and lay it on the cherries.
Brush 2 teaspoons whipping cream (or milk) on the edges of the pie crust. Then, sprinkle the remaining 1 tablespoon sugar on the brushed edges. The creamor milk will help the sugar stick to the crust and give the crust a golden brown color.
Bake at 400F, uncovered, for 25 to 30 minutes or until the pie crust is golden brown and the cherry mixture is bubbly. Let cool at least 10 minutes before serving to help set the filling. Melt remaining half of chopped chocolate with remaining 2 tablespoons whipping cream. Combine them in a small glass bowl and microwave 30 seconds.Stir until melted.You can drizzle the melted chocolate straight from the bowl with a spoon or fork. For more precise drizzling, put it in a snack size zip top bag and snip a tiny hole in one corner.Serve with ice cream or whipped cream, if you like!