No, Either "How many did you write?" (For a past action that is complete.) Or "How many have you written?" (A past action which could also suggest that you are still in the process of writing).
Note: You could also reword it as "You wrote how many?" This version, however, sounds as if you were requesting the person to repeat what they had said. For example: A. How many stories did you write? B. I wrote twelve. A. You wrote how many? (I did not hear what you said.)