Preheat your oven to 350°F (175°C). Line two large baking sheets with parchment paper or silicone baking mats and set them aside. Prepping the sheets ahead makes for easy cleanup later.

In a mixing bowl, whisk together the all-purpose flour and baking soda until well combined. This ensures the baking soda is evenly distributed throughout the dough.

In a separate medium mixing bowl, use a hand mixer to beat the salted butter and granulated sugar together until the mixture is light and fluffy. Add the egg and vanilla extract, then beat again until well incorporated. For best flavor, I like to use high-quality vanilla extract here.

Gradually add the flour mixture from Step 2 into the creamed mixture from Step 3 while beating on low speed until just combined. Scoop about 1 1/2 tablespoons of dough for each cookie, roll into balls with your hands, and then roll each dough ball in green sanding sugar to coat.

Arrange the sugar-coated dough balls on the prepared baking sheets, spacing them about 2 inches apart. Bake in the preheated oven for 10 minutes. The cookies should be set but still soft in the center.

Allow the cookies to sit out of the oven for about 3 minutes. Gently press a candy cane kiss into the center of each warm cookie. Let the cookies stand for a few more minutes before transferring them to wax paper or a baking rack to finish cooling. I always wait until the kisses just start to set before moving the cookies—otherwise, the candies can lose their shape.