Preheat over to 325. Grease bottom of foil pan or spray with non-stick coating.
In a 1-quart saucepan over low heat, melt chocolate chips and butter, stirring until melted. Remove from heat.
Stir in sugar and brown sugar until blended. Stir in eggs, one at a time, beating well after each addition. Stir in vanilla. Stir in flour and salt just until flour is moistened. Spread in pan.
Place pan on a baking sheet and bake for 35 to 38 minutes or until top is set and brownie begins to pull away from sides of pan. Slide pan off baking sheet onto a wire rack and cool brownies completley in pan, about 2 hours.
Cover tightly with foil and store in a cool place.