"The rice with onions is warmer than the porridge."
Translation:Рис с луком теплее, чем каша.
Can anyone please explain "теплеекаши" (an alternative correct answer, if you don't want to use "чем")? Obviously, I get that it's "warmer" and "porridge" just run together, which apparently makes: "warmer-than-porridge". When is it OK to do this, and perhaps more importantly, when is it not? Does it change the meaning or tone in any significant way, or are they two ways of saying exactly the same thing?
There are two ways to end a comparison: "чем + nominative" or just the word in genitive. To use the genitive, you have to use a comparative adjective with the -ee form (i.e. интереснее instead of более интересный). I know the genitive form is more common in spoken Russian, but there may be other nuances that I'm not aware of.