In a large mixing bowl, beat butter and powdered sugar for several minutes until well blended. Add in flour, salt, and vanilla. Beat for 2-3 minutes until dough starts to form a ball.
Press dough into a 9-inch-square baking dish lined with parchment paper. Bake for 21-25 minutes, until edges become lightly browned. Remove and cool completely.
While shortbread base is cooling, add caramel bits and whipping cream to a microwave-safe bowl. Microwave for 1 minute, stir and heat again for an additional 15-30 seconds. Stir until smooth. Pour over cooled (or mostly cooled) shortbread. Spread evenly.
Melt chocolate in a microwave safe bowl for one minute. Stir and heat an additional 30 seconds. Frost the top of the caramel and allow to set (about 30 minutes). Cut into bars and enjoy. It may be easier to refrigerate the bars and cut while slightly firm.
Notes
If you’re a fan of salted caramel, try topping these bars with a sprinkling of flaky sea salt.
Easily customize this recipe for a unique take on the classic Twix. You can add nuts to the caramel or even swirl the chocolate with peanut butter.
To help your caramel stick better, underbake the shortbread by a few minutes. Then, spread the caramel layer onto the base while the cookie is still warm (not hot) and the layers should adhere together.
Store these bars in an airtight container at room temperature. They’ll keep for 3-5 days.
Swap out the all-purpose flour for King Arthur Measure for Measure gluten free flour to make a gluten free treat.