Disclaimer: I am not trolling, I am an autistic person who doesn’t understand so many social nuances. Also I am from New Hampshire (97% white), so I just don’t have any close African-American friends that I am willing to risk asking such a loaded question.
Probably a lot of black families actually do have fried chicken, barbeque and cookouts are apparently a big part of the festivities traditionally.
If you find yourself becoming such good friends with a black person that they actually invite you to one of these cookouts, don’t bring fried chicken, or watermelons, or most of the stereotypical “black” foods, they’re considered black people food because the post civil war south fostered an environment of chronic black poverty on purpose that led to black families tending towards raising cheaper animals and growing cheaper crops for their own consumption.
So a white guy cracking watermelon or fried chicken jokes or bringing that kind of stuff to a black celebration comes across less as trying to share in the culture and more as rubbing salt in a, in many ways still open, wound.
As for what you should bring, bro just ask. Just making it known ya want to bring something for folks to enjoy will be good and appreciated, and if they decide they’d like to take you up on that, they’ll either give you a recipe off their list of stuff they’ve decided they want or ask what you think you can handle making and take your word on that if anything you feel confident making sounds good. Who knows, maybe that year will go down as the year that corned beef ya mentioned becomes a staple of the annual cookout!
What if they ask him to bring watermelon and chicken to the cookout? ;-)
Make sure you can go wide eyed enough that they start laughing if they were just razzing you