Combine the chocolate and peanut butter together in a large microwave safe bowl. Heat at 30 second intervals at 100% power, stirring well between heating, until the mixture is smooth and combined. Be careful not to overheat. You may also heat the chocolate and peanut butter in a saucepan over medium-low heat, stirring constantly until smooth.
Fold in marshmallows using a large rubber spatula.
Pour into greased 8-inch square pan.
Chill until firm, about 1 hour.
Cut into squares.
Store in an air-tight container at room temperature. Package in cellophane bags for gift-giving or add them to giveaway cookie platters and candy trays.
Keyword creamy peanut butter, mini marshmallows, semisweet chips