Line a 9 x 13 baking dish with foil extending over the edges. Set aside.

In a 2 quart heavy bottom pan, melt butter over low heat. Add sugar, water and corn syrup. Bring to a boil over medium high heat stirring constantly. Reduce heat to low/medium and continue stirring constantly, for about 15 minutes, or until candy thermometer reads 290°F. Once the desired temperature is reached, remove from heat and quickly stir in chopped cashews. Immediately add to foil lined baking dish and spread quickly.

After candy has sat for a few minutes, sprinkle chocolate chips on top, keeping approximately ⅛ cup of white chocolate chips aside. Let sit until slightly melted. Once melted, take a spatula and smooth over candy. Sprinkle remaining white chocolate chips on top of candy and let soften. Take a knife and lightly spread softened white chocolate chips in a zig zag design.

Chill in fridge for about 20 minutes or until firm. Once firm, lift foil out of baking dish and break into pieces. Store in a covered container and keep refrigerated for up to 3 weeks.