Preheat your oven to 350°F (175°C) and prepare two 9-inch round cake pans by greasing them with butter and dusting with flour.

In a mixing bowl, cream together the softened unsalted butter and granulated sugar using an electric mixer until light and fluffy (3-5 minutes).

Add the eggs one at a time, mixing well after each addition until smooth.

In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.

Gradually add the dry mixture and buttermilk to the butter mixture, alternating, and mix until just combined.

Stir in the vanilla extract and chopped, toasted pecans.

Divide the batter between prepared pans and bake for 25-30 minutes or until a toothpick comes out clean.

Cool the cakes in the pans for 10 minutes, then transfer to a cooling rack.

Beat the softened butter until creamy, then gradually mix in powdered sugar on low speed.

Add heavy cream and vanilla extract, mixing until fluffy.

Stack the cooled cakes, spreading frosting between layers and on the top and sides.

Decorate with extra pecans if desired.