With accent marks:
Ка́шу ма́слом не испо́ртишь.
You can't spoil the porridge with butter.
From time immemorial, porridge was loved and respected in Russia. It was cooked from wheat, buckwheat, oats, etc. To make it tastier, people added more butter.
This Russian proverb is used to say that something good can not be bad even in large quantities.
Other Russian proverbs
Put your trust in God, but don't make mistakes yourself
Do not look at a given horse's teeth.
The morning is wiser than the evening.
One in the field is not a warrior.
Make a fool pray to God - he will break his forehead.
Each sandpiper praises its swamp.
Water wears away a stone.
A titmouse in hands is better than a crane in the sky.