1. Place sugar, Karo syrup, water and butter in heavy 2 qt. stainless steel saucepan. Over MEDIUM heat, using candy thermometer, bring to 290-degree boil. Carefully swirl mixture occasionally. Bringing the mixture to correct boil can take several minutes, but it's important to watch the thermometer carefully so as not to scorch.
2. Remove from heat and add sliced almonds. Pour onto buttered, foil-covered cookie sheet.
3. Sprinkle white and chocolate chips over top. Lightly lay foil over cookie sheet to cover, 2-3 minutes. This will melt the chips. Remove foil from top and swirl chips with edge of knife. Cool at room temperature. Break into pieces.