Preheat the oven to 350 F. In a medium bowl, whisk together flour, salt, and baking soda. In a large bowl, combine butter with peanut butter, granulated sugar, and brown sugar. Add in the egg and vanilla extract, and mix until smooth.
Add in the flour mixture, mix until it is fully combined. Add in the green food coloring, and mix until it is fully green. Roll the cookie dough into balls and place onto a large ungreased baking sheet at least 2-inches apart. Place one sprinkle on each cookie. Bake for 10-12 minutes.