In a medium bowl, whisk to combine the flour, cocoa, and salt; set aside.
With a stand mixer or electric mixer on medium-high speed, beat butter and sugar until light and fluffy, about 2 minutes. Add egg yolk, milk, and vanilla; mix until incorporated. Reduce speed to low and add flour mixture, mixing until just combined.
Wrap dough in plastic wrap and refrigerate until firm, 1 hour.
Whisk the 2 egg whites in a bowl until frothy. Place chopped pecans in another bowl.
Roll chilled dough into 1-inch balls (a cookie scoop helps with this), dip each dough ball in egg whites, and then roll in pecans. Place balls about 2 inches apart on a baking sheet. Using a ½ teaspoon measuring spoon, make an indentation in the center of each dough ball.
Bake at 350 degrees F until set, about 12-14 minutes.
Meanwhile, microwave caramels and cream together in a small bowl, stirring occasionally, until smooth, about 2 minutes.
Once cookies are removed from the oven, gently re-press the indentations. Fill each well with caramel. Allow to cool until caramel is set.
Combine the chocolate chips and coconut oil in a microwave-safe bowl; microwave 1-2 minutes, stirring every 30 seconds. Using a spoon, drizzle over cookies in a decorative pattern. Allow chocolate to set before transferring to a container for storage or for serving.