Stir together cereal, flour, baking soda and salt.
In mixing bowl, blend butter and sugar. Stir in cereal mixture until thoroughly combined and crumbly. Press half of mixture into bottom of greased 2.5L ( 9" ) square baking pan. Bake at 180°C ( 350°F ) 8 -10 minutes for until lightly browned.
Meanwhile, melt caramels with milk in saucepan over low heat, stirring frequently until smooth. (OR, in 1 L / 4 cup glass measure, microwave mixture at HIGH 1 1/2 minutes or until smooth when stirred, stirring after 45 seconds). Set aside.
Sprinkle chocolate chips and walnuts over baked cereal layer. Cover evenly with melted caramel, then sprinkle with remaining cereal mixture. Press down lightly.
Bake at 180°C ( 340°F ) 15 - 20 minutes or until lightly browned. Cool completely. Cut into bars. Chill if desired.
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.