Directions

1. Grease a 9x13-inch baking pan.
2. Heat the corn syrup and marshmallows in a large saucepan over medium-low heat until marshmallows are melted, 5 to 7 minutes. Remove from heat, and stir in the crispy rice cereal. Press the cereal mixture into the prepared baking pan. Place a sheet of aluminum foil over the cereal mixture, and use a soup can to press the cereal together firmly to create a dense layer. Remove the foil, and spread the peanut butter on top, then refrigerate the pan.
3. Meanwhile, melt the chocolate chips with the vegetable oil in the top of a double boiler over just-barely simmering water, stirring frequently and scraping down the sides with a rubber spatula to avoid scorching. Once the chocolate mixture is smooth, allow it to cool slightly before spreading over the peanut butter layer. Return pan to the refrigerator, and chill until the chocolate layer has hardened, about 30 minutes. Cut into 36 bars.