Gather your ingredients so that you have everything close at hand on the counter or table. Lay out a piece of waxed paper, about 24" long. Coat with butter to prevent the cookies from sticking.
Premeasure the ingredients for a smooth cooking experience.
In a medium saucepan, combine 1/2 cup light corn syrup and 1/2 cup granulated sugar, mixing well. Bring to a rolling boil.
Remove from heat. With a wooden spoon, stir in 1 cup peanut butter. Mix well.
Add 2 1/2 cups Rice Krispies Cereal and mix until well coated.
Drop by teaspoonfuls onto the prepared waxed paper and let cool, up to an hour before serving. Makes 25-30 cookies.