Whisk together the flour, cocoa powder, baking powder, and salt in a bowl. Cream the butter and sugar in a separate bowl until light and fluffy. Add the egg yolk, vanilla extract, and 1/2 teaspoon of peppermint extract, and mix until well combined. Gradually add the dry ingredients to the wet ingredients, mixing until a dough forms.

Shape the dough into small balls and place them on a baking sheet lined with parchment paper. Flatten each ball slightly with the back of a fork. Bake in a preheated oven at 350°F (175°C) for about 10-12 minutes or until the cookies are set. Allow them to cool completely.

Combine the chopped chocolate, heavy cream, and vegetable oil in a microwave-safe bowl. Microwave in 20-second intervals, stirring after each interval, until the chocolate is melted and the mixture is smooth. Stir in 1/4 teaspoon of peppermint extract for that delightful minty kick.

Dip each cooled cookie into the minty chocolate coating, ensuring it’s fully coated. Place the coated cookies on a parchment-lined tray and let them chill in the refrigerator for about 20-30 minutes or until the chocolate has fully hardened.

Once the chocolate coating is completely set, your Frango Mint Cookies recipe are ready to be enjoyed! Serve these delectable treats on a beautifully arranged serving platter or place them in elegant gift boxes for sharing with friends and family. The combination of rich chocolate and refreshing mint will surely be a hit.