Interestingly, that word order is also valid English, though it has a slightly different meaning than "I like red cars".
Example: "I like [my] soup warm".
"I like soup warm, but you can eat it cold and left over if you want."
"I like having soup warm"
"I like my cookies freshly baked"
"I like men muscular and toned"
"I like my women blonde, so you can go for the brunette"
"I like cars red" doesn't quite work as well but doesn't seem wrong. Add a little context and it seems more normal. "As a buyer of many sports cars, I like my cars red, even despite the speeding tickets I get".
Perhaps a linguist could explain how this phrasing works.
(That said, of course I advocate teaching her to speak fluently and to use that word order only when she intends its subtlety of meaning.)
What do you want? - I want tea. How do you want your tea? - I want my tea hot with sugar.
I've noticed, say, that in Poland, where the native tongue lacks articles, people regularly mess up "the" and "a," or miss them altogether. I've never met a French person with the same issue, for obvious reasons.
When I started looking into people's mistakes with tenses in English - dear god, so much about my native tongue that I had no idea about, and yet made particular nationality error combinations really stand out. It's crazy fun.
Edit: and I love my eldest's progress with English. While she's basically a bilingual preschooler, she tends to speak English with polish word order: I like cars red. Her natural instinct is to also use the polish rules for nouns when choosing he/she/it. It's an absolutely fascinating process I feel privileged to observe.