Preheat the oven to 350°F (175°C) and prepare your cake pans.
In a large mixing bowl, cream the butter and sugar together until light and fluffy.
Add the eggs one at a time, mixing well after each addition.
In a separate bowl, combine the dry ingredients: flour, baking powder, baking soda, and salt.
Gradually add the dry mixture to the creamed butter and sugar, alternating with the buttermilk.
Stir in the toasted pecans and vanilla extract until evenly distributed.
Divide the batter evenly between the prepared cake pans.
Bake in the preheated oven for 25-30 minutes or until a toothpick comes out clean.
Allow the cakes to cool in the pans for 10 minutes before transferring to a wire rack.
Once completely cool, frost with buttercream frosting and garnish with additional chopped pecans, if desired.