Preheat your oven to 350°F (175°C). Spread the chopped toasted pecans evenly on a baking sheet and toast them for 7-8 minutes until golden and fragrant. Let them cool.

In a large mixing bowl, cream together 1 cup of softened unsalted butter, 1 cup of packed brown sugar, and 1 cup of white sugar with an electric mixer for 3-5 minutes until light and fluffy.

Add the 4 large eggs one at a time to the mixture, beating well after each addition. Follow by mixing in 2 teaspoons of vanilla extract.

In a separate bowl, whisk together 3 cups of all-purpose flour and 1 teaspoon of baking soda. Gradually add this dry mixture to the wet ingredients, alternating with 1 cup of buttermilk until just combined.

Gently fold in the cooled, toasted pecans using a spatula.

Pour the batter into a greased and floured Bundt pan or 9x13-inch cake pan. Bake for 45-55 minutes. Let cool for about 10 minutes before transferring to a wire rack.

To make the frosting, melt ¼ cup of unsalted butter in a saucepan. Stir in 1 cup of brown sugar until dissolved, then whisk in ¼ cup of heavy cream and remove from heat. Stir in 1 cup of powdered sugar until smooth.

Allow the frosting to cool slightly, then pour over the cooled cake and let it drizzle down the sides. Garnish with extra toasted pecans if desired.