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

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

Add the egg and vanilla extract to the butter-sugar mixture, mixing until fully incorporated.

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

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Fold in the crushed shortbread cookies.

Using a cookie scoop or a tablespoon, drop rounded portions of dough onto the prepared baking sheet, spacing them at least 2 inches apart.

Bake in the preheated oven for 10-12 minutes, until just golden around the edges.

While the cookies are baking, prepare the caramel filling by combining chewy caramel candies and heavy cream in a small saucepan over low heat, stirring until smooth.

When the cookies are out of the oven, use the back of a spoon to create a small indentation in the center of each cookie while still warm.

Spoon in a small amount of melted caramel into each indentation.

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

Melt the milk chocolate chips with vegetable oil in a microwave-safe bowl in 30-second intervals, stirring in between until smooth.

Drizzle the melted chocolate over the cooled cookies.