Preheat the oven to 350 degrees and place an oven rack in the center position.
In a large bowl, whisk together the flour, baking powder, baking soda and salt. Set aside.
In the bowl of an electric mixer, beat the butter and both sugars on medium speed until fluffy. Add the eggs, one at a time, incorporating completely before adding the next one. In a small bowl, whisk together the bourbon and heavy cream. Turn the mixer to low and add the flour mixture in thirds alternating between the flour mixture and bourbon/cream mixture until everything has been added.
Pour the batter into two 9 inch cake pans coated with butter and bake for 40-45 minutes or until a cake tester inserted into the center comes out clean. Allow the cakes to cool for 5 minutes and then turn out onto a cooling rack to cool completely.
For the cake soak:
In a small bowl, whisk together the heavy cream and bourbon for the cake soak. Brush the bottom of a cake with 1/2 the soak and then repeat with the remaining layer. (Cake can be made in advance and wrapped in plastic wrap after this point, keep at room temperature for up to 24 hours.)
For the frosting:
In the bowl of an electric mixer, beat the butter and cream cheese until smooth. Slowly add the powdered sugar 1/2 cup at a time until completely incorporated. Once the frosting has reached a stable consistency, turn the mixer to med-high and beat for 2 minutes or until the frosting is fluffy and light in color. Transfer to an airtight container and store for up to 24 hours at room temperature if not using immediately.
For the salted caramel sauce:
In a medium saucepan, mix together the sugar and water. Bring the mixture to a boil over med-high heat. Continue boiling until amber in color, approximately 2-3 minutes. Carefully stir in the butter and remove from the heat. VERY carefully add the heavy cream and salt. (It will bubble up violently.) Allow the caramel to cool to room temperature before using.
To assemble the cake:
Place one layer on a cake plate or serving platter. Spread two tablespoons of caramel sauce over the bottom layer and then spread 1/2 cup of the frosting over the caramel. Top the frosting layer with the remaining cake layer and spread 1/2 cup of frosting over the top layer. Add a thin layer of frosting to the sides and place in the refrigerator for 10-20 minutes to allow the frosting to set. Remove from the refrigerator and, using all but 1 cup of frosting, frost the entire cake with an off-set spatula creating a smooth surface all the way around.
Carefully press the pecans around the bottom half of the cake.
Pour 1/2 cup caramel sauce into a zip top bag and snip off one corner. Drizzle the sauce on top of the cake being careful to stay one inch from the side of the cake.
Add the remaining frosting to a pastry bag fitted with a 1M cake tip (open star) and pipe the frosting around the top edge of the cake. Allow the cake to chill in the refrigerator for 2 hours or up to 24 hours.
Bring the cake to room temperature for 30 minutes before serving.