Combine the cornstarch and salt in a heavy saucepan. Whisk in 1/2 cup cold milk until the mixture is smooth. Gradually whisk in the remaining milk and 3/4 cup maple syrup.

Cook over medium heat until thickened and bubbly. Stir frequently starting out but as the mixture heats, stir constantly to keep from scorching. Reduce the heat to low once it begins bubbling and cook an additional 2 minutes, stirring constantly. Remove from heat.

In a separate small bowl, whisk the egg yolks. Whisking constantly, add a 1/4 cup of the hot milk mixture to the egg yolks. Slowly and whisking constantly, add the egg yolk mixture into the saucepan containing the milk mixture.

Over medium-low heat, cook the mixture until it begins to bubble, then cook an additional 2 minutes, stirring constantly. Remove from heat and whisk in the butter.

Cool to room temperature without stirring.

Once filling has cooled, add 1 cup heavy cream to a chilled medium-size bowl. Whip on high until soft peaks form. Reduce speed to low and slowly add 2 tablespoons confectioners' sugar. Increase speed and beat until stiff peaks form.

Whisk 1 cup of the whipped cream into the fully-cooled filling. Pour into the cooled pie crust.

Spread the remaining whipped cream over the pie filling.

Refrigerate overnight. Just before serving, whip the remaining 1/4 cup heavy cream on high speed until soft peaks form. Reduce speed and add 1 tablespoon confectioners' sugar, then increase speed and beat until stiff peaks form. Using a piping bag and large star tip, pipe the whipped cream around the edges of the pie to decorate.

Refrigerate any leftovers.

If you want to make this using non-dairy milk and non-dairy whipping cream, add an additional 1 tablespoon cornstarch to the saucepan before adding the non-dairy milk. I used almond milk. For the whipped cream, I used the Silk brand, and found I needed to increase the amount of cream used since it doesn't whip up as the same volume as regular cream. Whip the full 1-1/4 cups for adding to the pie and topping it, and then an additional 1/3 to 1/2 cup for piping around the edges. The confectioners sugar measurement remains the same.