Prepare the Pecans:

1. Preheat the oven to 350°F.
2. Melt the butter in a small skillet over medium-low heat. Stir in the pecans and light brown sugar. Cook, stirring frequently, for 3–4 minutes until the pecans are toasted and fragrant.
3. Spread the pecans on a parchment-lined baking sheet and let them cool.

 Make the Cake Layers:

1. Grease three 9-inch cake pans, line the bottoms with parchment paper, and dust the sides with flour. Shake off the excess.
2. Mix the buttermilk and milk in a small bowl and set aside.
3. In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.
4. Beat the softened butter, granulated sugar, and vanilla extract using a stand or handheld mixer until light and fluffy.
5. Add the eggs one at a time, mixing well after each addition.
6. With the mixer on low, alternate adding the flour mixture and milk mixture in three parts, starting and ending with the dry ingredients. Mix until just combined.
7. Fold in the toasted pecans with a spatula.

Bake the Cakes:

1. Divide the batter evenly among the prepared pans.
2. Bake for 25–28 minutes or until a toothpick inserted into the center comes out clean.
3. Let the cakes cool in their pans for 15 minutes before transferring them to a wire rack to cool completely.

4. Prepare the Cream Cheese Frosting:

1. Beat the butter and cream cheese together until smooth and creamy.
2. Add the vanilla extract and gradually mix in the powdered sugar. Beat until fluffy.

Assemble the Cake:

1. 1. Level the cooled cake layers with a serrated knife or cake leveler.
   2. Place one layer on a serving plate or cake stand. Spread 1 cup of frosting evenly over the top.
   3. Repeat with the second layer. Add the final layer and frost the top and sides of the cake.
   4. Decorate with swirls of frosting, toasted pecans, or other embellishments as desired.