Preheat oven at 350. Melt 3/4 cups chocolate chips, in a saucepan over lowest heat. When chips begin to melt, remove from heat; stir. Return to heat for a few seconds at a time, stirring until smooth. Cool to room temperature. In a mixing bowl, combine melted chocolate chips, margarine, vanilla, and egg whites. In another mixing bowl, combine flour, remaining chocolate chips, sugars, baking soda, and salt . Mix wet ingredients with dry ingredients just until moistened. Drop dough by rounded tablespoons onto prepared baking sheets. Bake for 12 minutes or until edges are set but centers are still soft. Recipe By : Nestle Toll House Best Loved Cookies