In a bowl, whisk together the pumpkin puree and vanilla. Let sit for five minutes while flavors combine.
In a heavy 2-quart saucepan over medium heat, combine 1 1/2 cups of the cream and the brown sugar. Cook until bubbles form around the edges of the pan, about 5 minutes.
Meanwhile, in a separate bowl, combine the egg yolks, cinnamon, pumpkin pie spice, nutmeg, salt, and the remaining 1/2 cup cream. Whisk until smooth.
Remove the cream mixture from the heat. Gradually whisk about 1/2 cup of the hot cream mixture into the egg mixture until smooth to temper the eggs. Then pour the entire egg mixture back into the pan.
Cook over medium heat, stirring constantly keeping the custard at a low simmer until it is thick enough to coat the back of the spoon and leaves a clear trail when a finger is drawn through it, 4 to 6 minutes. Do not allow the custard to boil.
Whisk the pumpkin mixture into the custard. Cover with plastic wrap, pressing it directly on the surface of the custard to prevent a skin from forming. Refrigerate until chilled, at least 3 hours or up to 24 hours.
Transfer the custard to an ice cream maker and let spin for one hour before freezing. Add the bourbon during the last ten minute of the churning. Transfer the ice cream to a freezer-safe container. Cover and freeze until mostly firm, about 2-3 hours.
While the ice cream freezes, start the waffle taco shells. Whip eggs whites and sugar with an electric mixer until fluffy and soft peaks.
Add flour, melted butter, vanilla, cinnamon, salt, and milk. Mix on high until no lumps remain. Let the mixture sit for ten minutes.
Use a waffle cone maker to cook waffle pancakes using 2-3 Tbsp. batter per cone. (Alternatively, you can use a regular nonstick pan with non-stick spray. Spread the batter out to make a very thin pancake and cook on med-high, flip after 1 min.)
Remove waffle pancake from iron or pan and shape into a taco by draping it over a thin book or the slots in an over rack allow to cool and harden.
Once waffle tacos are cool, fill with slightly softened pumpkin ice cream and place back into the freezer to harden completely. Dip them in chocolate, top them with nuts, caramel, or whatever your heart desires!