Cookie dough: Combine flour, cocoa and salt. In a separate bowl mix butter and sugar until light and fluffy, 2-3 minutes. Mix in the egg yolk, milk, and vanilla. Stir in flour mixture, just until combined.

Chill dough in the refrigerator for one hour.

Preheat oven to 350 degrees F. Line a baking sheet with parchment paper.

Pecan coating: Whisk egg white in a bowl until frothy. Place finely chopped pecans in another shallow bowl. Remove cookie dough from fridge and roll into 20 small balls. Roll each dough ball in the frothy egg whites, and then roll and press in the chopped pecans. Place on baking sheet.

Indent: Use the back of a small measuring spoon to make an indentation in the center of each dough ball.

Bake at 350 Degrees F for about 10-12 minutes, or just until set. Don't over-bake (cookies will harden as they cool). As the cookies come out of the oven, gently re-press the indentations with a small spoon.

Caramel: In a microwavable bowl, mix the caramel bits and water. Microwave at 30-second intervals, stirring after each interval, until caramel is melted (1-2 minutes). Pour small spoonfuls of caramel into the indented cookies.

Optional Chocolate Drizzle: Melt chocolate in a double boiler or in the microwave until smooth. Drizzle cookies with melted chocolate. Sprinkle with flake salt, if desired.