Preheat the oven to 350 F. In a large bowl, whisk together flour, sugar, cocoa powder, salt, and baking soda.
Add in melted butter, eggs, and peppermint extract, and whisk until smooth. Using a cookie scoop, place cookies onto a large ungreased baking sheet at least 2-inches apart.
Bake for 10-12 minutes. Remove from the oven and top each cookie with one unwrapped chocolate kiss.