peanut butter chip triangles

Ingredients For peanut butter chip triangles

• 1 1/2 c

  all purpose flour
• 1/2 c

  light brown sugar
• 1/2 c

  (1 stick) cold butter
• 1 2/3 c

  (10 oz.) pkg. reese's peanut butter chips,divided
• 1 can

  (14 oz.) sweetened condensed milk ( not evaporated)
• 1

  egg,slightly beaten
• 1 tsp

  vanilla extract
• 3/4 c

  chopped walnuts
• powered sugar (for dusting)