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 F 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.)