Preheat the oven to 325°F (163°C). Line a 9 x 9-inch baking dish with non-stick aluminum foil, leaving an overhang to lift the bars out after baking.
Unwrap the caramels and place them in a microwave-safe bowl with the heavy cream. Microwave briefly, stirring every 15–20 seconds, until smooth and pourable; set aside to cool slightly.
In a medium bowl, whisk together the all-purpose flour, baking soda, and salt until evenly combined.
In a separate large bowl, combine the melted, slightly cooled butter with the brown sugar and granulated sugar until uniform.
Add the whole egg, egg yolk, and vanilla extract to the butter-sugar mixture and mix until fully incorporated.
Stir the dry ingredients into the wet ingredients until just combined, then fold in the chocolate chips.
Press half of the cookie dough evenly into the bottom of the prepared pan.
Carefully pour the caramel sauce over the dough, leaving a small border around the edges.
Dollop the remaining dough over the caramel in pieces. Gently pat the top with your fingertips to cover as much caramel as possible; it is okay if some caramel peeks through.
Bake for about 30 minutes, or until the top is golden brown and the bars are slightly firm to the touch.
Remove the pan to a wire rack and let cool completely. Use the foil overhang to lift the bars from the pan, then cut into squares. For cleaner slices, chill briefly before cutting and bring to room temperature to serve.