To make the filling: Reset the oven to 325° degrees F. In a medium non-reactive saucepan whisk together the half-and-half and Clabber Girl Cornstarch until well blended and smooth. Whisk in the cream. Heat, whisking, over medium-high heat until it boils and thickens slightly, about a minute. Set aside to cool for 5 minutes.
Using a whisk, beat together the maple syrup, eggs, salt, and vanilla in a large, heat-proof bowl until very well blended. Whisking, very slowly pour the hot cream mixture into the egg mixture in a thin stream to avoid overheating (and possibly curdling) the eggs. Strain the custard through a fine sieve into the pie shell.
To bake the pie: Place on a rimmed baking sheet in the middle third of the oven; bake for 15 minutes. Reduce the heat to 300° F., and continue baking until the filling appears set except in the center when the pan is jiggled, about 20 to 25 minutes. Transfer the pie to a wire rack until cooled, then refrigerate, covered, at least 2 hours and up to 3 days before serving. Serve chilled, cut into wedges. Add a dollop of whipped cream, if desired.
Tip: In this and other baked goods, it's best to use medium or dark amber grades of maple syrup; they have a more robust flavor and deeper color than the fancy, grade A light maple syrup. They are usually less expensive, too!