So i want to make my nephew a cookie cake for his birthday party, but my sibling suggested I make a sort of single serving version just for him.

I already had a cookie cake recipe set aside to make, but it's for a 9 inch cake and i already tried making the recipe but in smaller sizes and it was kind of a dud. Should i just make a normal cookie batch and just make 2 or 3 bigger cookies and stack them with frosting as a "cake"? Or should i just try to make the cookie cake work? I don't actually have smaller pans so i'm using aluminum foil to act as the edges of a pan like the recipe below shows

This is the cookie cake recipe i'm using. Not really sure if it's any different from regular cookies