Yes, gluten-free burger is possible.
Then it turns out, they put the gluten-free bun in the same oven as the other buns.
So, burger without bun, which is weird.
They offered to provide some fries instead (which were gluten-free). Ok, I’m not that difficult, so accept that offer.
But I don’t expect those few fries to end up on my bill for €4,-
— Not very
— No gluten-free information on the menu
— Some
— Average