In a medium bowl, whisk together the flour, baking soda, and salt. In the bowl of an electric mixer (or a large bowl if mixing by hand), combine the dulce de leche, egg, vanilla extract or paste, and golden syrup or corn syrup. Mix until smooth, then add in the dark brown sugar and granulated sugar, stirring until fully incorporated. Gradually add the dry flour mixture to the wet ingredients, mixing just until combined. Gently fold in the toffee bits followed by the grated chocolate. Chill the cookie dough for about 1 hour, or until it is firm and no longer sticky to the touch.

When ready to bake, preheat your oven to 350°F (177°C) and line a baking sheet with parchment paper. Use a 2-tablespoon scoop to portion out dough balls, rolling each one between your palms to form a smooth sphere. If you want to fill the cookies with a caramel center, tear each dough ball in half, place a caramel candy in the middle, press the two halves back together, and roll again to completely enclose the caramel in a smooth ball. Arrange the dough balls on the prepared baking sheet, spacing them about 2 inches apart.

Bake the cookies for 10 to 12 minutes, until the edges are lightly golden and the centers are set but still soft. Allow the cookies to cool on the baking sheet for 3 minutes before transferring them to a wire rack to cool completely.

For the drizzle, place the chocolate chips in a resealable plastic bag and microwave for about 1 minute until melted. Knead the bag gently to smooth out the chocolate, then snip a tiny corner off the bag to pipe the melted chocolate over the cooled cookies. Place the remaining 20 caramels in a microwave-safe bowl and heat for about 1 minute, stirring until smooth and at drizzling consistency. If needed, continue microwaving in 10-second intervals. Use a spoon to drizzle the caramel in a zigzag pattern over the cookies, then repeat with the melted chocolate. Allow the drizzles to fully harden at room temperature for several hours before storing.

Cookies will stay fresh for at least 1 week when stored in an airtight container or zip-top bag at room temperature. To enjoy a soft, melty caramel center, microwave each cookie for about 10 seconds before serving.