"Are you a good cook?" accepted 10 Aug 2017, although I think "Do you cook well" is a more accurate translation. The accepted answer is idiomatically and colloquially more acceptable, it's just not what the sentence says - and, since the more literally translation is perfectly acceptable English, it would be my preferred answer.
Yes, @mightypotatoe is correct that "Are you cooking good?" sounds completely unnatural to a native English speaker. The phrases "Are you good at cooking?" or "Do you cook well?" make more sense and are grammatically correct, though I feel that at least when asking about cooking, "Are you a good cook?" is how the question would most commonly be phrased. In this case 'cook' is a noun as in 'a person who prepares meals'. There are some words like this in English where the verb and the noun are the same. For example, a couple I can think of right now are:
to cook / a cook, ie "The cook is cooking." "Is he a good cook?" to host / a host, ie "The host is hosting a party." "Is she a good host?"
I hope that helps.