Preheat oven to 350 degrees. Grease your 9x13 pan, preferably glass.

Add together the flour, sugar, cocoa, baking soda, and salt in a bowl and combine with a whisk.

Add the eggs, buttermilk, oil, and vanilla into the bowl of your stand mixer, and using the paddle attachment mix together on medium-low.

Add the dry ingredients to the buttermilk mixture.

Mix together well until fully incorporated.

Boil your water and add a small amount to the batter, give it a quick stir and add the remaining boiling water and mix together.

Pour batter into the 9×13 greased pan.

Bake at 350 for 30-35 minutes or until a toothpick comes out clean when inserting into the center of the cake.

Add the butter to the bowl of your stand mixer.  With the paddle attachment, cream the butter on medium speed until the butter is smooth.

Turn the speed of your mixer to low and gradually incorporate the powdered sugar.

Pour in the caramel and vanilla extract.

Beat frosting on a medium setting for 5-10 minutes until the frosting is light and fluffy.

Let the caramel sauce come to room temperature or if firm, microwave for 15-20 seconds or as needed till soft and pourable.

When done baking the cake, use the end of a wooden spoon (not too thick) to poke 12-18 holes into the cake going across and down the cake.

Pour 1 cup of caramel sauce over the cake while it is hot.  If the sauce has thickened, microwave for 20 or 30 seconds to soften at 50% power.  Do not boil.

Set the cake aside to cool completely; ideally overnight in the refrigerator.

Once the cake is cooled spread a layer of the caramel buttercream frosting on top.

Chop the pecans and sprinkle them on top of the frosting

Drizzle with 1/2 cup of caramel sauce.