Hi Lais "I cook for you" is the best option. Though you would normally need to change the tense also and say "I will cook for you." or "I am cooking for you." "I cook you" is grammatically correct, BUT not normal. Think about the sentence "I cook fish." What do you cook? The fish. Therefore if you say "I cook you." What do you cook? .... "I cook to you." = not correct English Hope this helps Chris

Either use "for" or, if you mention the direct object after the IO, no preposition: I'm cooking you dinner. Do *not* just say "*I'm cooking you" ;)