Line a square baking dish with parchment paper and set aside.
Preheat oven to 400 degrees. Pierce sweet potato in several places with a fork or knife. Place in oven to roast over a sheet pan for 40 minutes or until skin is wrinkled and flesh is tender. Remove sweet potato and lower oven temperature to 350 degrees.
1 sweet potato
Allow sweet potato to cool until safe to handle (about 10 minutes) then carefully remove skin. Cut sweet potato into a few large pieces and place into blender or food processor. Pulse until a puree forms (about 30-45 seconds).
While sweet potato is cooling, add caramel candies, 2 teaspoons sea salt, and one tablespoon milk to a nonstick saucepan and melt over medium heat. Stir together until uniform to form a salted caramel sauce, which will be very sticky (about three minutes).*I recommend using a non-stick pot and cooking over no higher than medium heat to avoid burning the bottom of the caramel and winding up with a difficult mess to clean up later. 11 ounces caramel candies, 2 teaspoons fine sea salt, 1 tablespoon milk
Mix together flour, ½ teaspoon sea salt, baking powder, and cinnamon.
2 cups all-purpose flour, 1 teaspoon baking powder, ½ teaspoon fine sea salt, 1 teaspoon ground cinnamon
Add sweet potato puree, brown sugar, milk, melted butter, and vanilla extract to bowl. Stir until uniform and no dry pockets remain. Batter will be thick and sticky.
¾ cup brown sugar, ½ cup unsalted butter, 2 teaspoons vanilla extract, ¾ cup milk
Spread batter into prepared baking dish. Pour salted caramel back and forth over batter then use a butter knife to swirl the caramel throughout the batter.
Bake for about 50 minutes or until a toothpick inserted between caramel swirls comes out dry (not clean). Bars will be dense and gooey. Let cool completely then cut into nine pieces.