Preheat the oven to 350°F (175°C) and line a muffin tin with cupcake liners.
In a medium bowl, whisk together the flour, baking powder, baking soda, salt, and cinnamon.
In a large mixing bowl, cream the softened butter and granulated sugar together until light and fluffy, about 3-4 minutes.
Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
Gradually add the dry ingredients to the butter mixture, alternating with the buttermilk. Mix until just combined.
Fold in ½ cup of the salted caramel sauce until evenly distributed.
Divide the batter evenly among the cupcake liners, filling each about two-thirds full.
Bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cupcakes to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.
In a small bowl, mix the powdered sugar and milk until smooth to create a glaze. Once the cupcakes are cool, drizzle the glaze over the top.
Finish with a drizzle of extra salted caramel sauce and a pinch of sea salt for garnish.