First, coat a standard cookie sheet with the ½ teaspoon of butter (so the mixture can be immediately poured into the pan). Then bring the sugar and 2 cups of sugar to a boil in a heavy sauce pan over a medium/low heat, stirring constantly. Then cover and cook for another 2 or three minutes.
Add the almonds and stir uncovered until it reaches the hard-crack stage (a candy thermometer reaches 300° F and mix is a golden brown). Pour the mixture onto the cookie sheet, taking care not to scrape the sides of the sauce pan). After the candy cools for about two minutes sprinkle with the chocolate chips. Let it cool for another two minutes and then spread the now melted chips like an icing. Sprinkle with the walnuts and use a spatula or back of a spoon to gently press the walnuts into the icing. Place in a refrigerator for 10 minutes.Melt the semi-sweet chips in the microwave or sauce pan, and stir until smooth. Drizzle over the cooled candy and return to the refrigerator for another 10 minutes. Melt the white chips and shortening and drizzle the candy again. Let the candy cool for about an hour or two before breaking into pieces.