Preheat the oven to 350°F (175°C) and grease two round cake pans with baking spray.
In a large bowl, combine the dry ingredients: flour, sugar, cocoa powder, baking powder, baking soda, and salt. Whisk together until well blended.
In a separate bowl, whisk together the wet ingredients: eggs, buttermilk, oil, and vanilla extract until smooth.
Gradually add the wet mixture to the dry ingredients, stirring until just combined. Do not overmix; the batter should be slightly lumpy.
Divide the batter evenly between the prepared cake pans and level the tops gently.
Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted in the center comes out clean.
Allow the cakes to cool in the pans for 10 minutes before transferring to wire racks to cool completely.
Once cooled, drizzle layers with caramel sauce and sprinkle chopped pecans over the top.
Stack the two layers, pouring more caramel on top and decorating with additional pecans if desired.
Serve and enjoy your Chocolate Turtle Cake, garnished as desired with remaining caramel and pecans.