Preheat oven to 375°F (190°C) and line a baking sheet with parchment paper.

In a large bowl, cream together softened butter and granulated sugar until light and fluffy.

Beat in the egg and vanilla extract until well combined.

Gradually stir in the all-purpose flour and salt until a cohesive dough forms.

Shape the dough into 1-inch spherical balls.

Roll each dough ball in the pastel-colored sanding sugar until thoroughly coated.

Place the balls on the prepared baking sheet, spacing them approximately 2 inches apart.

Bake for 8 to 10 minutes until the edges are set.

Immediately upon removal from the oven, press one chocolate kiss firmly into the center of each cookie.

Transfer the cookies to a wire rack to cool completely until the chocolate is stable.