For the Cake:

1. Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.

2. In a large bowl, whisk together flour, sugar, baking powder, baking soda, and salt.

3. In a separate bowl, beat together buttermilk, softened butter, eggs, and vanilla extract.

4. Gradually add the wet ingredients to the dry ingredients, mixing until smooth.

5. Divide the batter evenly between the prepared pans.

6. Bake for 25-30 minutes or until a toothpick inserted into the center comes out clean.

7. Allow the cakes to cool in the pans for 10 minutes before removing them and cooling completely on a wire rack.

For the Caramel Frosting:

1. In a saucepan over medium heat, melt the butter. Stir in the brown sugar and heavy cream.

2. Bring the mixture to a gentle boil, and cook for 3-4 minutes, stirring constantly.

3. Remove from heat and stir in vanilla extract.

4. Gradually whisk in powdered sugar until smooth and thickened.

5. Allow the frosting to cool slightly before spreading it on the cooled cake.

Assembling the Cake:

1. Place one layer of the cooled cake on a serving plate.

2. Spread a generous amount of caramel frosting over the top of the first layer.

3. Top with toasted pecans.

4. Place the second layer of cake on top and repeat the frosting and pecan topping.

5. Garnish the top with additional toasted pecans and serve.