I'm not coming cos
A) no invite lol
B) you might give me beans and egg on the same plate ( but with toast)
C) you might give me pineapple then I would die! No allergic just extremely adverse!
Trying to think, my mate invited me round and asked if there's anything I won't eat, my answer was celery and pineapple, which would be a weird meal!
If BF mum had asked you could have said, fat, oil, cream, cheese, bread, flour, or lied and said you were Coeliac, lactose intolerant and on a low fat diet!
Seriously though do you want her discussing this with the family? You know what families are like, she tells DIL that you asked for this (in a nice way) but DIL takes offence and whines to BFs brother, brother thinks you're out if order and tells uncle Jack, uncle Jack can't see the problem and annoys BFs brother, brother takes it to Gma, who agrees that during the war they were glad of it etc etc, before you know it the wedding breakfast will need United Nations to keep the peace!