Preheat the oven to 350°F (175°C). Grease and flour a 9x5 inch loaf pan, or line it with parchment paper.

In a large mixing bowl, cream together the softened butter and sugar until light and fluffy. This should take about 3-5 minutes.

Add the eggs, one at a time, mixing well after each addition. Stir in the vanilla extract.

In another bowl, whisk together the all-purpose flour, baking powder, and salt.

Gradually add the dry mixture to the wet mixture, alternating with the buttermilk. Begin and end with the flour mixture. Mix until just combined.

In a small bowl, combine the ground cinnamon and chopped pecans. Fold half of this mixture into the batter until evenly distributed. Reserve the other half for swirling later.

Pour half of the batter into the prepared loaf pan. Drizzle half of the caramel sauce over the batter. Sprinkle half of the reserved cinnamon-pecan mixture. Pour the remaining batter over this, followed by the rest of the caramel and the final cinnamon-pecan topping. Use a knife to swirl the caramel gently through the batter.

Bake in the preheated oven for 55-60 minutes, or until a toothpick inserted into the center comes out clean.

Once baked, let the pound cake cool in the pan for about 10 minutes, then transfer to a wire rack to cool completely.

Serve warm or at room temperature, optionally topped with whipped cream or ice cream and additional caramel sauce.