In a large mixing bowl, beat the softened butter and confectioners' sugar together until they're wonderfully light and fluffy. Stir in the peppermint extract to infuse that delightful minty aroma.
Grab a separate bowl and gently whisk together the flour, cornstarch, and salt. Gradually add this dry mixture into your creamy butter mixture, blending just until a soft, smooth dough forms. Remember, less is more when mixing!
Cover the dough and pop it into the refrigerator for at least 30 minutes. This simple step helps the cookies hold their perfect shape beautifully when baked.
Preheat your oven to a cozy 350°F (180°C). Once your dough is chilled, roll it into small, 1-inch balls. Place them about 2 inches apart on an ungreased baking sheet.
Bake for just 9-11 minutes, or until the bottoms are very lightly browned. Carefully transfer the cookies to a wire rack to cool completely. Patience is key for perfect meltaways!
In a small bowl, beat the softened butter until it's creamy. Gradually mix in the confectioners' sugar, milk, and peppermint extract. If you're feeling festive, add a few drops of red food coloring until your frosting is smooth and spreadable.
Once your cookies are fully cooled, spread a lovely layer of frosting over each. Then, sprinkle generously with crushed peppermint candies for that extra holiday sparkle. Let the frosting set before serving these delightful treats!