Q. A child that usually follows his family tradition and eats only products that contain Cholov Yisroel, but when he finds himself with a group of friends, out of peer pressure he eats kosher chocolates that are not Cholov Yisroel, should he make a brocho on them? Is there a need for hatoras nedorim and at what age?
A. Horav Shlomo Miller’s Shlit’a opinion is that since the Maharsham and others permit cholov stam when it is a mixed ingredient and Tzitz Eliezer (16:25) maintains that even those who are stringent agree that chocolate made with powdered milk is permissible, in this particular case concerning a child one may be lenient and he should recite a brocho. Even id he is already twelve years old, he does not need to be matir neder, as one can rely on the declaration made on Erev Rosh Hashana.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a