In a medium bowl combine flour, cocoa, and salt.

With electric mixer on medium-high speed, beat butter and sugar until light and fluffy, about 2 minutes. Add egg yolk, milk, and vanilla and mix until incorporated.

Reduce speed to low and blend in flour mixture. Cover dough and refrigerate for one hour.

Preheat oven to 350 degrees.

Whisk egg whites in a bowl until frothy. Place chopped pecans in another bowl. Roll chilled dough into 1-inch balls, dip in egg whites, and then roll in pecans, coating evenly.

Place cookies about 2 inches apart on a lightly greased baking sheet. Using a 1/2 teaspoon measuring spoon, make an indentation in the center of each dough ball. Bake for 8-10 minutes, or until just set.

Meanwhile, microwave the caramels and cream together in a small bowl for one minute. Stir and return to the microwave in 20-30 second increments, until caramel is melted and smooth.

Once cookies are removed from the oven, gently re-press the indentations. Fill each indentation with about 1/2 teaspoon of the caramel mixture.

Cool on the pan for about 10 minutes before transfer to a wire rack to cool completely.

Prepare the Chocolate Drizzle (optional). Place chocolate in a small zip-top plastic bag. Set bag in a bowl of warm water to soften. Gently knead the chocolate with your fingers until melted and smooth, placing back in the warm water for a minute or two as needed.

Alternately, chocolate can be melted in the microwave at 50% power. Snip a small corner from the bag and drizzle chocolate over cookies.