This is a recipe for Moonlight-style cookies that can be easily made using pancake mix. The ingredients are just four: unsalted butter, granulated sugar, egg yolk, and pancake mix. Soften the butter in the microwave, then mix in the sugar, egg yolk, and pancake mix in that order. Chill in the refrigerator until firm. Afterward, roll the dough into a ball, flatten it, make a wavy pattern with a fork, and bake in the oven. Using egg yolk and granulated sugar results in a rich, crisp, and authentic cookie with a melt-in-your-mouth texture. It's easy enough for beginners to make, making it a perfect baked good for a home café or a snack to bake with children.