Preheat oven to 350~F. Lightly grease 2 cookie sheets. In a food processor, blend sugars, butter, egg whites and vanilla until fluffy, stopping once to scrape down sides of work bowl, about 1 minute. Add peanut butter and process until combined, about 20 seconds. Add flour, baking soda and salt; blend until Just combined, using 2-3 on/off turns (Do Not over-process). Transfer mixture to a large bowl. Stir in chopped candy bars. Mound dough by 1-1/2 tablespoonfuls onto prepared sheets, spacing 2 inches apart. Flatten slightly using fingers. Bake until dry in appearance and centers are still slightly soft to touch, about 15 minutes. Cool on cookie sheets until fairly cool or they'll fall apart on you. Transfer to a rack to cool completely. Store in an air-tight containger. Can be prepared ahead. Store 4 days at room temperature or freeze 3 weeks.