Preheat the oven to 350°F (175°C) and apply a uniform coating of non-stick spray to a 9x13-inch metal baking pan.

In a large mixing bowl, sift together the flour, sugar, cocoa powder, baking soda, and salt.

Incorporate the buttermilk, vegetable oil, and eggs using a whisk until the mixture reaches a smooth consistency.

Gradually pour the hot coffee into the batter, stirring continuously until fully integrated; the batter will be thin.

Transfer exactly 50% of the chocolate batter into the prepared pan and bake for 15 minutes or until the surface has just set.

While the base layer bakes, combine the caramels, evaporated milk, and unsalted butter in a heavy-bottomed saucepan over medium-low heat.

Stir the caramel mixture constantly until the components are fully emulsified and the texture is smooth.

Remove the par-baked cake from the oven and distribute the chocolate chips and 1 cup of toasted pecans evenly over the top.

Pour the warm caramel emulsion over the layer of chocolate chips and pecans.

Carefully pour the remaining cake batter over the caramel layer, smoothing it to the edges with an offset spatula.

Return the pan to the oven and bake for an additional 25 to 30 minutes, or until a tester inserted into the top cake layer comes out clean.

Allow the cake to cool completely at room temperature for at least 2 hours to ensure the internal caramel layer stabilizes before slicing.