PREHEAT oven to 375° F.
BEAT peanut butter, brown sugar, butter and 1/2 cup granulated sugar in large mixer bowl until creamy. Beat in egg and vanilla extract. Gradually beat in flour and baking soda.
SHAPE dough into 1-inch balls. Roll in 1/4 cup granulated sugar; place on ungreased baking sheets.
BAKE for 7 to 9 minutes or until lightly browned. Immediately press 1 Nestlé Heart into center of each cookie (cookie will crack around edges). Cool cookies on baking sheets for 2 minutes; remove to wire racks to cool completely.