Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large mixing bowl, cream together the softened butter with granulated and brown sugars until light and fluffy, about 2-3 minutes.

Add the egg and vanilla extract, mixing until fully combined.

In a separate bowl, whisk together the all-purpose flour, baking soda, and salt.

Gradually add the dry ingredients to the wet ingredients and mix until just combined.

Fold in the crushed shortbread cookies.

Using a cookie scoop or tablespoon, drop rounded portions of the dough onto the prepared baking sheet, keeping about 2 inches apart.

Bake for 10-12 minutes or until the edges are golden brown and centers look slightly underbaked.

While the cookies are baking, melt the chewy caramel candies with heavy cream in a small saucepan over low heat, stirring until smooth.

Once cookies are out of the oven, make a small indentation in the center of each cookie with the back of a spoon.

Spoon a small amount of melted caramel into the indentation of each cookie.

Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack.

Melt milk chocolate chips with vegetable oil in a microwave-safe bowl, then drizzle over the cookies and let set.