Do you know how many Jews it takes to make a roast? Nein.
What would drive you to make off-color jokes about Jewish people?
It's a joke. Jokes are supposed to lead to being entertained.
Jokes are entertaining when they are not about serious subjects. You can hurt people by joking about race, class and religion. Learn when to use humor and when not to before you start making jokes about Jewish people getting burned.
I thought I was making friends here and what have I done?
You're probably not going to make friends, even though I can see now that this was your intention, by putting down an entire faith. People will think that you're kind of weird instead of funny.