1.  Combine flour, cocoa, and salt in bowl. With electric mixer on medium-high speed, beat butter and sugar until fluffy, about 2 minutes. Add egg yolk, milk, and vanilla and mix until incorporated. Reduce speed to low and add flour mixture until just combined. Refrigerate dough until firm, overnight is best

2. Rroll dough into 1-inch balls,  roll in pecans. Roll again pressing the nuts intpo the ball. Place balls 2 inches apart on prepared baking sheets. Using teaspoon measure, make indentation in center of each ball. Bake until set, 10 to 12 minutes, switching and rotating sheets halfway through baking.

3. using a simple double boiler by using a glass mixing bowl set onto a small sauce pan of boiling water. Melt caramels and milk in bowl, stirring occasionally, until smooth, 3-5 minutes until smooth

4. Once cookies are removed from oven, gently press existing indentations with teaspoon measure. Fill each with ½ teaspoon caramel mixture. Cool 5 minutes, then transfer to wire rack and cool completely.