Prepare the Crust:

1. In a small bowl, stir together the crushed cookies, melted butter and salt until combined. Scrape into a lightly buttered 9-inch pie dish. Using the bottom of a cup or a flexible spatula, press the crumbs firmly into an even layer along the bottom and up the sides of the pie dish.

Prepare the Filling:

1. In a medium-sized saucepan set over medium-low heat, melt the butter and brown sugar together until bubbly. Whisk in the milk and cream, and bring the mixture to a bare simmer, stirring occasionally.
2. In a medium-sized mixing bowl, whisk the eggs and corn starch until smooth. Ladle in a little of the hot milk, whisking as you go to make sure the eggs don't curdle. Repeat this process again until you've added about half of the milk, then pour the contents of the bowl back into the saucepan.
3. Continue cooking the pudding until thickens, stirring constantly with a wooden spoon or heat-resistant spatula to keep the bottom from burning. Remove from heat and stir in the bourbon. Set aside to cool for 5 minutes, then pour into the prepared pie crust. Let cool to room temperature, then transfer to the refrigerator to chill for 3-4 hours (or overnight) to allow the filling to set up.

Prepare the Topping:

1. Just before serving, prepare the topping. Using a mixer, beat the heavy cream, icing sugar and bourbon into soft peaks. Spread onto the chilled pie filling, and sprinkle with pecans, if using. Serve immediately.