For the crust, add the cookies and pecans into a food processor and process until the mixture is in small crumbs. Add the sugar, cinnamon, salt and butter, and pulse until the butter is evenly distributed.
Pour the crust mixture into a nine-inch tart pan and press with the bottom of a glass or measuring cup to evenly coat the bottom and up the sides. Make sure the crust mixture is firmly pressed together.
Put the pan onto a baking sheet and bake the crust for about 10 minutes or until it's set. Remove the pan the oven and set it aside to cool.
Turn the oven down to 250 degrees.
Heat a saucepan over low heat, and add the milk and cream. Stir regularly to keep it from scorching on the bottom, and once the milk just starts to bubble a little around the edges of the pan, remove it from the heat and stir in the chocolate, continuing to stir until the chocolate is completely melted.
In a mixing bowl, combine the eggs, pumpkin puree, cinnamon, ginger, cloves and nutmeg, and stir until it's well combined.
Add about one-fourth cup of the chocolate mixture into the pumpkin mixture to temper the eggs. Add the rest of the chocolate mixture, stirring well. Finish it out by adding the bourbon or vanilla extract and stirring again.
Pour the mixture into the prepared crust and bake on the baking sheet for 30 to 35 minutes or until the tart is just barely jiggly in the middle. Remove the tart from the oven and let it cool completely before serving.