BLEND BUTTER, SUGARS, EGG,AND VANILLA UNTIL FLUFFY, STOPPING ONCE TO SCRAPE DOWN SIDES OF BOWL, ABOUT 1 MIN. ADD FLOUR,BAKING SODA AND SALT AND MIX UNTIL JUST COMBINED. DO NOT OVER MIX. STIR IN WHITE CHOCOLATE CHUNKS AND NUTS. MOUND DOUGH BY 1/3 CUPFULS ONTO LIGHTLY GREASED COOKIE SHEET, SPACE ABOUT 2 IN. APART. BAKE IN PREHEATED 375 DEGREE OVEN UNTIL LIGHLY BROWN AROUND EDGES, ABOUT 15 MIN.COOL ON COOKIE SHEET FOR 3 MIN, THEN REMOVE TO RACKS AND COOL COMPLETLEY. STORE IN AIR-TIGHT CONTAINER. (CAN BE PREPARED AHEAD. STORE COOKIES UP TO 4 DAYS AT ROOM TEMP. OR FREEZE 3 WKS.)