Preheat your oven to 350°F (175°C). Cream together the softened butter, granulated sugar, and brown sugar in a large mixing bowl using an electric mixer for about 3-5 minutes until light and fluffy. Add the eggs one at a time, mixing well after each addition, then stir in the vanilla extract. In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add the dry mixture to the wet ingredients, mixing until just combined.

Bake the cookie base for 15 minutes. Remove from the oven and drizzle the caramel sauce evenly over the warm cookie layer. Sprinkle the chocolate chips over the caramel layer, then crumble the remaining cookie dough over the top. Return to the oven and bake for an additional 20-25 minutes until the top is golden brown.

Allow the cookie bars to cool in the pan for at least 30 minutes. For easier cutting, refrigerate for an additional 30 minutes. Prepare the chocolate topping by melting the chocolate chips and vegetable oil in a microwave-safe bowl in 30-second intervals until smooth. Drizzle the melted chocolate over the cooled cookie bars and let it set before cutting into squares.