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
If you are chasing two hares at once, you won’t catch a single one.
Don’t wave your fists after the fight.
Live for a century, learn for a century, but die being a fool anyway.
A well-fed man does not understand a starving one.
All is well that ends well.
You see your friends in the times of trouble.
In a quiet whirlpool, demons live.
Without labor, you can not even catch a fish in the pond.