Preheat oven to 350 degrees.
Combine first 5 ingredients in a large mixing bowl. Stir until combined.
Add remaining cake ingredients to the wet ingredients. Mix until just incorporated, being careful not to overmix.
Spray a 9x13 pan with non-stick cooking spray, and then pour batter into the cake pan.
Bake cake for 35-40 minutes or until a toothpick inserted in the middle comes out clean.
Remove cake from oven and let cool on a cooling rack.
Add brown sugar, unsalted butter, and milk to a small saucepan and heat over medium heat to make the caramel sauce, frequently stirring until thickened. Remove the pan from the burner, and add vanilla.
Let the caramel sauce cool.
Poke holes in the cake with the end of a rounded wooden spoon.
Pour caramel sauce over the cake and push into the holes, making sure to reserve some sauce for the top of the cake.
Beat the cream cheese until smooth and then mix in the powdered sugar, heavy cream, and vanilla. Fold in the whipped topping, and then spread the cream cheese mixture over the top of the cake.
Decorate the top of the cake with drizzles of caramel and chopped pecans.