Preheat the oven to 350 F. In a medium bowl, whisk together flour, salt and baking soda. In a large bowl, mix together butter, peanut butter and sugar until fluffy. Add in egg and vanilla extract and mix until smooth. Add in the flour mixture, and mix until it is fully combined.
In a medium bowl, whisk together flour, cocoa powder, salt and baking soda. In a large bowl, mix together butter and sugar until fluffy. Add in egg and vanilla extract and mix until smooth. Add in the flour mixture and mix until it is fully combined.
Take a small amount of each cookie dough and roll together into balls. Place the cookies onto a large ungreased baking sheet at least 2-inches apart. Bake for 10-12 minutes.