Using a mixer, whip the heavy whipping cream until it is light and fluffy. This should take about 1-2 minutes. Refrigerate the whipped cream until you're ready to add it to the pie.
Separate the eggs, the whites into one bowl and the yolks into another. Beat the egg whites until they are stiff and hold a peak (as in meringue). Refrigerate the egg whites to add to the filling later.
Use a fork to lightly whisk the egg yolks. Set aside.
In a heavy-bottomed saucepan over medium heat, whisk together the milk and maple syrup. Whisk often and reduce heat slightly if necessary so the milk does not scorch. Heat this until it is very hot, but just before it boils.
Once the sugar milk/sugar mixture is almost to a boil, pour about 1/2 cup of the hot syrup into the egg yolks and whisk quickly for 10-15 seconds. Then pour this mixture back into the syrup mixture on the stove. Cook and stir this mixture for 3-4 minutes over medium-low heat.
Next you'll get the gelatin ready. In a small bowl, mix one envelope of unflavored gelatin with 1 tablespoon of water. Whisk this softened gelatin into the syrup mixture and stir for an additional 2 minutes. The lumps of gelatin will dissolve and disappear.
Take the mixture off the stove and let it sit for 5 minutes. Then place the pot in the refrigerator for 20 minutes to cool.
When the sugar mixture has cooled, pour it into the egg whites and fold together. Then gently fold in the heavy whipping cream.
Lastly, you'll pour the creamy mixture into a baked pie shell, top with your favorite chopped nuts and refrigerate for at least 4 hours so that the pie has time to cool and firm up.
The calories shown are based on the pie being cut into 8 pieces, with 1 serving being 1 slice of pie. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate.