My sister made this often and I always enjoyed it.
Bakers frequently err by dumping hot liquid fat directly into un-sifted flour, creating stubborn clumps that survive even vigorous stirring. Using a sturdy heavy-bottomed saucepan for melting the initial fat and cocoa mixture prevents scorching and ensures a smooth emulsion before it hits the dry goods.
Thoroughly toasting the chopped pecans beforehand deepens their nutty profile within the sweet topping. Proper cooling prevents the delicate crumb from fracturing when portioned.