Preheat the oven: Set your oven to 350°F (175°C). Line a baking sheet with parchment paper or a silicone mat.
Mix ingredients: In a bowl, combine peanut butter, sugar, and egg. Stir until smooth and fully incorporated.
Form cookie balls: Using your hands or a small cookie scoop, roll the dough into 1-inch balls.
Bake: Place cookie balls on the prepared baking sheet, spaced about 2 inches apart. Bake for 8–10 minutes, until lightly cracked on top.
Add chocolate kisses: Remove cookies from the oven. Immediately press a chocolate kiss into the center of each cookie. The warmth will slightly melt the chocolate without losing its shape.
Cool: Let cookies cool for 5 minutes on the baking sheet, then transfer to a wire rack if desired. Enjoy warm or at room temperature.