You drink kwaśne mleko with potatoes.
Hahaha! You don't "drink" kwasne mleko. I eat it with a spoon! Yammyyyy, anyway. And, make sure the potatoes are sprinkled with chopped dill. :)
Also, in the summer, you crush fresh, ripe strawberries, add some sour cream and sugar, then pour it over hot, home made noodles. Ah, to die for.