Beat butter and sugar until it looks fluffy, about 2 minutes.

Add vanilla and egg and beat until it is creamy in appearance, about 90 seconds.

Add salt and baking soda, cocoa powder. Mix until well blended.

Blend in flour until the dough has a nice, uniform brown color.

Add the chopped chocolate to the dough and mix for 30 seconds.

Divide the dough in half.

Place the dough into a large food storage bag or use plastic wrap to form a log of dough. Seal and repeat with the other half.

Place the dough in the freezer for 25 minutes.

Preheat the oven to 325 degrees.

Line cookie sheets with parchment paper or use baking mats.

Roll the logs of dough in the granulated sugar you sat aside.

Slice the logs of cookie dough about a ½” thick.

Place the slices about 2” apart on the cookie sheets and bake for 10-12 minutes.

Allow to cool on the cookie sheets for 5 minutes before removing.

Store leftovers in an airtight container.