In a saucepan, combine the butter, brown sugar, vanilla, and bourbon. Heat this over medium heat until it begins to bubble. Let is bubble for a minute then remove it from the heat.
Measure out a half cup of the sauce and let it cool. The remaining sauce can be left in the saucepan or placed in a dish. Set those aside for now.
In a bowl, whisk the eggs until they are well blended.
To the eggs add the half & half, milk, and sugar. Pour in the 1/2 cup of cooled caramel sauce. Whisk these together.
Add in the pecans. Stir these together.
In a large bowl, place 8 cups of sourdough bread that have been cut or torn into 1/2 inch pieces. Add in your egg mixture and fold them together.
Pour the mixture into an oiled shallow 2-quart casserole dish. You can also use a 9×13 baking dish.
Cover the dish tightly with foil. Bake for 30 minutes, then remove the foil and bake another 10-15 minutes or until the pudding is set in the center when you jiggle the dish.
Warm up the reserved caramel sauce and drizzle it over the servings.