In large microwavable bowl, mix cereals, cashews and raisins.
In 2-cup microwavable measuring cup, microwave butter, mustard, honey and seasoned salt uncovered on High 1 to 2 minutes or until butter is melted and mixture is hot; stir. Pour over cereal mixture; toss to coat. Microwave uncovered on High 5 to 6 minutes, stirring every 2 minutes, until mixture begins to brown.
Spread on waxed paper or foil to cool. Store in airtight container.