"I want to cook borshch."
Translation:Я хочу готувати борщ.
Both work for describing cooking something in a saucepan.
But this sentence doesn't sound too natural. It uses an imperfective form of the verb, which means the speaker wants to spend some time cooking (i.e. the important part is the process and not the result), or to cook something regularly. I think «Я хочу приготувати/зварити борщ» with a perfective verb would sound better.