Combine the sifted flour, cocoa, and baking soda.
In another bowl, whisk softened butter until creamy, add salt, vanilla, both types of sugar, and beat for about 2 minutes.
Add half of the flour mixture and stir until smooth. Then add the rest and mix again.
Add chocolate chips and stir.
Place the dough on a countertop, halve it, and form two logs 1 1/2 "in diameter. Wrap each in plastic wrap, refrigerate for 3 hours.
preheat oven to 325F, line two baking sheets with parchment. Slice the chocolate logs into 1/2 "slices and place on the parchment 1" apart. Bake for 10 minutes. Cool for 5 minutes then removes from baking sheet.