Preheat your oven to 350°F (175°C). Line a 12-cup muffin tin with cupcake liners and set aside.
In a medium mixing bowl, sift together the flour, baking powder, baking soda, and salt. Set aside.
In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.
Beat in the eggs, one at a time, followed by the vanilla extract.
Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk, and mix until just combined. Be careful not to overmix.
Fold in the caramel sauce until evenly distributed throughout the batter.
Divide the batter evenly among the prepared cupcake liners, filling each about two-thirds full.
Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted into the center comes out clean.
Remove the cupcakes from the oven and let them cool in the muffin tin for 5 minutes before transferring them to a wire rack to cool completely.