You were wondering if you could eat/drink butter or cream, dispite a
milk protein allergy:

1 cup of milk has 9 g protein
1 cup of cream has 7 g protein
1 cup of butter has 2 g protein

Information is from "Nutrient values of some common foods" by Health
and Welfare Canada.

I have a milk protein allergy and react to cream and butter.  I find if
I stay away from butter I don't miss it so much and margarine starts to
taste o.k.  I don't like coffee without cream, so it has actually helped
me give up coffee.