In large bowl, combine the flour, pecans, sugar, baking powder, baking soda, and salt. In separate bowl, beat egg yolks and melted butter. Add slowly to the mixture alternating with buttermilk.
Substitute for buttermilk (if desired): Place 1 1/2 cups milk or heavy cream and juice from one lemon in jar with lid. Shake and let sit for a few minutes to thicken.