Unwrap 36 peppermint kisses and place them in a bowl. Freezing them for about 30 minutes is advisable to help maintain their shape when pressed into the cookies later.
Preheat your oven to 350°F and line a baking sheet with parchment paper.
In a large bowl, cream together ½ cup unsalted butter and ¾ cup sugar using a hand mixer or stand mixer until the mixture is light and fluffy, which should take about 3 minutes.
Mix in 1 egg, ½ tsp pure peppermint extract, and 1 tbsp whole milk until well combined.
In another bowl, whisk together 1 ¼ cups + 2 tbsp all-purpose flour, ⅛ tsp salt, and ¼ tsp baking powder. Gradually combine this dry mixture with the wet ingredients, mixing until a cohesive dough forms.
Using your hands, roll the dough into tablespoon-sized balls. Once rolled, coat them in a mixture of green and red colored sugars or toss with the red, green, and white nonpareils to make them sparkle.
Place the cookie balls on the prepared baking sheet, ensuring they are spaced about 2 inches apart as they will spread while baking.
Bake in the preheated oven for about 12 minutes. They should be lightly golden brown. Allow them to cool for about a minute and then gently press a frozen peppermint kiss into the center of each cookie.
Finally, transfer the cookies to a cooling rack to finish cooling. Enjoy your delightful creation!