Preheat oven to 350 degrees Fahrenheit
In a large bowl (or mixer) cream margarine with sugars until light and fluffy (I find it takes a good 5 minutes).
Beat in eggs and vanilla. Will take on the consistency of an icing.
In a medium bowl sift together flour, cocoa, baking soda and salt. Stir into your creamed mixture.
With a wooden spoon stir in chocolate chips and nuts.
Divide dough into four portions (I literally use the spoon to make indents in the dough while it is in the bowl so I get even "logs")
On lightly greased baking sheet shape two of your portions into logs (approx 12x1 1/2")
Bake for 15 minutes until toothpick comes out clean (keep in mind you have chocolate chips in there, so there will be some shiny goodness that comes out!)
Cool for about 10 minutes and then drizzle the white chocolate across the tops. Cut on a diagonal (aprox 1") slice!