When you have "adjective+noun" in English and you have to turn into Portuguese, you'll have most of time de, not "com". Racing car = carro de corrida, chocolate cookie = biscoito de chocolate. Cookie WITH chocolate = biscoito com chocolate.
biscoito de chocolate = the chocolate is in it in a way you cant take it out. leite com chocolate = you decide to add chocolate in it, you can take them separate. biscoito com chocolate = you can choose the cookie with or without chocolate.