Preheat your oven to 350°F (175°C). Spread the pecans on a baking sheet and toast for about 8-10 minutes until golden and fragrant. Remove from the oven, then melt 2 tablespoons of unsalted butter in a skillet over medium heat. Add the toasted pecans with a pinch of salt, sauté for 2-3 minutes, then set aside to cool.

In a large mixing bowl, sift together 2 cups of all-purpose flour, 1 teaspoon of baking powder, 1/2 teaspoon of baking soda, and 1/4 teaspoon of salt. Give it a gentle whisk to ensure even distribution.

In a stand mixer or a large bowl, beat 1 cup of room-temperature unsalted butter, 1 cup of granulated sugar, and 1/2 cup of light brown sugar together on medium speed until the mixture is fluffy and pale.

Add 3 large eggs to the butter mixture, one at a time, ensuring each egg is fully incorporated before adding the next. Pour in 1 teaspoon of vanilla extract and mix until smooth.

Gradually add the dry ingredient mixture to the wet mixture while alternating with 1/2 cup of buttermilk. Start with the flour mixture and finish with it, mixing on low speed until just combined. Fold in the cooled toasted pecans gently.

Divide the batter evenly between two greased and pecan-dusted round cake pans. Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out clean.

Once baked, remove the cake layers from the oven and let them cool in the pans for about 10 minutes. Carefully transfer them to cooling racks to cool completely.

While the layers cool, prepare your frosting. In a mixing bowl, beat 8 ounces of softened cream cheese and 1/2 cup of unsalted butter together until smooth. Gradually add 4 cups of powdered sugar, along with 1 teaspoon of vanilla extract and 2-3 tablespoons of heavy cream.

Once the cake layers are completely cool, place one layer on a serving plate. Spread a generous amount of frosting on top, then add the second layer and frost the top and sides of the cake.