Prepare the chocolate buttermilk cake per the directions. Bake in a buttered and floured bundt pan for 40-45 minutes or until a toothpick inserted into the center comes back clean. Cool in the pan on a cooling rack.
Spread the pecan pieces in a single layer on a sheet pan. Toast in a 350°F oven for 6-8 minutes Set aside to cool.
To make the caramel-pecan sauce: In a heavy bottomed saucepan over medium-high heat melt together the brown sugar, heavy cream, butter, corn syrup and salt. Bring to a boil then lower the heat to a simmer. Cook for 2 minutes stirring constantly.
Remove the caramel sauce from the heat then add the vanilla and toasted pecans. Stir until the pecans are coated. Set aside to cool slightly.
To make the ganache: in a microwave safe bowl, melt the chocolate chips and heavy cream in 20 second increments stopping to stir each time. Repeat until completely smooth.
Place the bundt cake on a cake pedestal or platter. Drizzle with 1/3 of the chocolate ganache and 1/3 of the caramel pecan sauce. Repeat drizzling the cake on all sides until both of the sauces are used.
Store chilled bringing to room temperature for serving.
The caramel-pecan sauce and chocolate ganache should still be warm but still pourable before drizzling onto the cake.