Preheat the oven to 350 F. 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 the egg and vanilla extract and mix until smooth.
Add in the flour mixture and mix until it is fully combined. Add in the food coloring. Use a cookie scoop to 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 one with a chocolate kiss.