Preheat your oven to 400°F (200°C).
Place the unbaked pie shell into a 9-inch pie plate.
Spread the rhubarb evenly over the bottom of the pie crust.
In a large mixing bowl, combine the sugar, salt, and cornstarch. Mix well to ensure there are no lumps.
Beat the eggs in a separate medium bowl and then add them to the sugar mixture. Pour in the heavy cream and stir until the mixture is smooth and well combined.
Carefully pour the custard mixture over the rhubarb in the pie crust.
Place the pie in the preheated oven and bake at 400°F (200°C) for 15 minutes. Place a pie shield over the edges to prevent burning.
After 15 minutes, reduce the oven temperature to 350°F (175°C) and continue baking for an additional 40-45 minutes. The pie is done when the custard is set in the center of the pie. You can take the pie shield off about half way through cooking for nice, golden brown edges.
Remove the pie from the oven and let it cool on a wire rack. Allow it to cool completely before slicing to ensure the custard sets properly.