In a medium bowl, whisk together the flour, cocoa powder, and salt. Set aside.

In a large bowl or stand mixer fitted with a paddle attachment, cream the butter and sugar together at medium speed until light and fluffy, about 1 to 2 minutes.

Beat in the egg yolk, milk, and vanilla until combined.

At low speed, add the flour mixture and mix just until combined. Cover and chill dough in the refrigerator for 1 hour to firm up.

After chilling, preheat the oven to 350°F and line a baking sheet with parchment paper and set aside.

Beat egg whites with a fork until frothy.

Use a medium cookie scoop to portion out the dough and roll into balls.

Dip the balls of dough in the eggs whites and then roll in the pecan pieces and place on the prepared baking sheet 2 inches apart.

Use the back of a round teaspoon to make an indent in the center of the balls, pressing down gently so you don't crack them too much.

Bake for 10 to 12 minutes, rotating the baking sheet halfway through.

While the cookies are baking, add the caramels and heavy cream to a medium bowl and microwave at 30-second intervals, stirring between each one until smooth, about 2 minutes.

Remove cookies from the oven and repress the teaspoon into the indent again and fill the indent with the caramel sauce and allow to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.

Melt the chocolate melting wafers or chocolate chips in the microwave at 30-second intervals, stirring after each one until melted. Drizzle over the cooling cookies.