To be honest not my favorite burger patty I’ve ever eaten. But they have a gluten free bun. And options to easily customize your burger which is huge for a restaurant in Warsaw. It worked well for our family.
Always check this link to check what products are gluten free at the moment: (Polish version) https://faq.maxpremiumburgers.pl/guide/ktore-produkty-nie-maja-glutenu-w-skladzie?category=alergie-i-skladniki