In a mixing bowl, cream the butter and both sugars. Add egg whites and beat well. Blend in peanut butter and vanilla. Combine flour, baking soda, and salt and add to the creamed mixture. Mix well. Stir in candy bars. Shape into 1 ½ balls and place on greased baking sheets. Bake at 350°F for 10 to 12 minutes or until golden brown. Cool on wire racks. Yields 4 dozen.