1. In large heavy saucepan over low heat, melt butter. Stir in sugar and corn syrup. Cook over medium heat, stirring constantly, until sugar is dissolved and mixture is bubbly. Remove from heat.
2. Blend in peanut butter and vanilla. Add cereals and peanuts, stirring until thoroughly coated.
3. Press firmly and evenly into buttered 2 L (9") square pan. Chill until set, about 45 minutes. Cut into squares. Store covered at room temperature.
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.