In saucepan over medium heat, combine brown sugar, corn syrup, peanut butter and butter; cook, stirring and without boiling, until melted and smooth. Remove from heat. Stir in Rice Krispies* and peanuts.
Evenly spread in parchment paper-lined 9-inch (2.5 L) square metal cake pan. Refrigerate until firm, about 30 minutes.
Chocolate Frosting: Meanwhile, in bowl, whisk cocoa powder with water until smooth. Add butter; beat with spoon until smooth. Add icing sugar in 2 batches, beating until smooth and adding up to 1 tbsp (15 mL) more water if necessary. Stir in vanilla. Spread evenly over squares. Refrigerate until icing is firm. Cut into squares.
YIELD: 49 squares.
In keeping with good allergy practices, we remind you to be aware of allergens and to check labels on any packaged goods used. This recipe has been tested using Kellogg's* products. Results with other products may vary.