Brown the Butter: Melt 1 cup of unsalted butter in a saucepan over medium-low heat. Increase the heat to medium until the butter turns a rich brown color, then pour it into a heatproof bowl to cool.

Preheat Oven: Preheat your oven to 350°F (175°C). Grease three 8-inch round cake pans generously with butter.

Mix Dry Ingredients: In a medium bowl, combine the cake flour, granulated sugar, brown sugar, baking powder, baking soda, and salt. Mix well to blend the dry ingredients.

Combine Ingredients: Pour the browned butter into the dry mixture and stir until combined.

Prepare Wet Mixture: In a separate bowl, whisk together the buttermilk, eggs, and vanilla extract. Gradually add this wet mixture to the flour mixture, stirring until just combined. Gently fold in 1 cup of finely chopped pecans.

Bake: Divide the batter evenly among the three prepared pans. Bake for about 30 minutes, or until a toothpick inserted in the center comes out clean. Allow cooling in the pans for 15-20 minutes before turning out onto wire racks to cool completely.

Prepare Frosting: In a large mixing bowl, beat the softened butter, cream cheese, brown sugar, vanilla, and salt until smooth and creamy. Gradually add the sifted confectioners’ sugar and heavy cream, beating until the frosting is light and fluffy.

Assemble Cake: Once the cakes are completely cooled, frost the top of one layer, then add the second layer and frost again. Repeat with the third layer, applying a generous coat of frosting on the top and sides. Sprinkle the remaining finely chopped pecans on top for decoration. Chill the cake and serve at room temperature.