Preheat the oven to 350°F (175°C). Line a baking sheet with parchment paper.
In a medium bowl, combine the peanut butter, granulated sugar, egg, and baking soda. Mix until smooth and well combined.
Roll the dough into 24 equal-sized balls, about 1 inch in diameter, and place them on the prepared baking sheet about 2 inches apart.
Bake the cookies for 8 to 10 minutes, until the edges are set but the centers are still soft.
Remove the baking sheet from the oven. Immediately press one Hershey’s Kiss into the center of each cookie, gently flattening it slightly.
Allow the cookies to cool on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely.