Line bottom of an 8x8x2 inch pan with aluminum foil; smooth out wrinkles.
Place chocolate in a microwave-safe bowl. Microwave at 100% power, checking every 30 seconds, until melted. Stir chocolate until smooth.
Stir cereal and raisins into chocolate until well combined. Spread mixture evenly in prepared pan. Refrigerate about 2 hours or until mixture is firm.
Invert pan onto a work surface; remove pan and peel off aluminum foil. Cut into squares and serve. Squares can be stored in an airtight container in refrigerator up to 2 weeks.