I think there might be arguments!

At the risk of being controversial......
I'm finding more and more that vegetarians and vegans expect meat eaters to compromise (ie not eat meat in their presence) whilst not being prepared to compromise on their own position. I KNOW this is a huge generalisation and that it isn't as black and white as that but more of my vegetarian friends are becoming increasingly strident

I have two vegetarian daughters-in-law. They wouldn't dream of being so rude as to criticise what other people eat in our house. They both have different religious observances, too, but have never imposed those observances onto my house.

In your position, I'd make sure the vegetarian food was kept strictly apart from anything else and then tell your daughter that otherwise, it's your house and your rules.

sluttygran as a long term veggie I think you need to speak to your DD before Boxing Day. As her mother tell that her family accepted her decision to be vegan a long time ago. They respect her decision as her personal decision and the time has come when she must accept the personal decisions of the rest of the family not to be vegan (even if she does not respect their decision). As her mother and hostess explain that you will be serving vegan and non-vegan food and she needs to accept the situation and not spoil the day for everyone else.

If she is naturally argumentative (as are my family) as you say, then she will have something to say back to you (!), but as her mother you will probably need to be blunt and tell her it's time for her to shut up about this.

We have a mixture of veggies and non-veggies in our family, but none of us would try to impose our decision on the others. That goes for my friends too and quite frankly I would have no friends left if I went on like your DD.

As for the day itself, maybe having a sit down buffet would make things a little easier? Then the non-vegan might try some of the vegan options and that might appease her a bit. At the moment she sounds like a nightmare.

Best of luck.

I think that Wilma offers very good advice on this, in fact I can’t add to it. Good luck!

All the vegetarians I know are like Wilma’s family, they just accept that some people eat meat and others don’t and don’t preach.

I have met meat eaters who go on and on and on, as nauseum, quizzing vegetarians about their lifestyle choice though.

Both need to shut up and allow everyone to feast in peace.

Tell them beforehand you don’t want this behaviour at your table.

I am a meat eater who has "quizzed" vegans and vegetarians but only because I am interested in how easy or difficult it is to find places that cater to them (apparently this is getting easier), do they have "celebration" foods (like we have turkey at Christmas). Just as I am curious about the traditions of someone from another culture, so I am interested in the reasons someone chooses to be vegetarian or vegan - a choice incidentally which I respect.

I should have added that any vegetarian or vegan I have spoken to have always been happy to answer my questions

Buffet? One table with meat etc and one with vegan/veggie?

Not all ‘quizzing’ is as civilised as yours though sunseeker

Tell her (before the day) to respect your house and that it's your decision about what you will serve food wise to your guests. She must come across meat eaters in lots of other places.

We serve a complete vegan buffet, so there's no faffing about what might or might not be in something, with one huge glorious ham, kept quite separate.
If your DD wishes to fuss and preach at something like that, then she is doing it to annoy, and needs to be called out on it.
Although it is rather expensive, and honestly, you could sit down and sort out the menus yourself, I have found this book useful: www.goodreads.com/book/show/25622732-vegan-vegetarian-omnivore

I d definitely cook for both as you would expect to, but not have any argument over comments etc
The best Christmas I ever had included two Muslims a Buddhist, a Christian, a vegetarian and me a meat eater everything went on the table so each put on their plate what they found acceptable plus a meaty gravy and a vegy gravy We had a ball but it all depends on acceptance

Surely your DD wouldn’t be so bad mannered as to create bad feeling over the food choices of others. My DD is a vegetarian but her partner is not and neither is their child. She wouldn’t dream of imposing her food choices on others, and would get short shrift if she did. I am another who is with Wilma on this one. Let her see the lie of the land before Boxing Day.

They are brother and sister . Surely the topic has come up before and a solution was found.

In our family there are everything from enthusiadtic carnivores to vegans. One vegan has celiac disease and one vegan anaphylaxis, being extremely allergic to eggs, all dairy products and sesame.

Xmas dinner is not as difficult as you might imagine. I serve turkey with sausage stuffing, pigs in blankets and turkey gravy, but everything else is vegan and cooked separately, eg roast potatoes cooked in sunflower oil and loads of other vdg. The vegan centrepiece is a festive raised pie made from gluten free flour and veg shortening pastry filled with mushrooms and chestnuts and topped with cranberries served with vegan gravy.

Whatever happened to manners?
Both children are quite happy to impose their preferences on you and criticise others who don't share them , thus spoiling the meal for everyone. Plus the fact they are also happy to put you to double the trouble of preparing two separate meals, to accommodate their beliefs. Do they offer to help?
Tell your son and daughter before the meal you have provided food to accommodate everyone, and There Will Be No Criticism.

I've found a curry buffet with one meat dish cooked in the slow cooker works well. Lots of tasty vegan dishes in Indian cuisine. Just a suggestion.

sluttygran do you think your daughter would accept that her behaviour is simply rude?
A few years ago my strictly vegan nephew was visiting from Australia in the summer and his mother thought it would be a good idea for them to join us on a barbecue Sunday! My nephew brought his own nuts and seeds and refused even to eat the salad and vegan options I'd made, I suspect it was because it had been prepared in the same kitchen as meat. He kept himself aloof during the whole afternoon and could have caused a difficult atmosphere if we hadn't all just ignored his churlishness.

After catering for both tastes I would not allow any conflict about what is being served I would have to tell them to grow up and be civil to each other and other guests and to appreciate the time and effort that has gone into the catering for them.

I'm afraid I wouldn't allow hissy fits. How about appreciating the time and trouble the food will have taken to prepare and cook, and the fact that you're lucky enough to have family to share it with?

DD is vegetarian but would not dream of making a fuss about the food.

Recently when one of Minibaggs's friends was coming for a stay over and would eat at our house, Minibaggs told me that her friend is a vegetarian but "will eat meat if that's what you've prepared". That, to me, is the essence of politeness— not imposing your choices and beliefs on others, especially when you are a guest in their house.

I think too many vegetarians and vegans present an intolerant and rather fanatical food face to the world. They need to understand and to tolerate that other people are as free as they are to think and behave differently and it is not the job of other people to be constantly accommodating their limited choices. Vegetarians and vegans have every right to make choices for themselves. They do not have any right to make choices that inconvenience other people.

PS We had a vegetarian meal that we often have. I didn't cook any bacon that we often have with it. MrBaggs and I think most nice vegetarian meals are even nicer with a bit of bacon ?

I think all of us face problems with friends and family with eating restrictions of all kinds, whether principled (vegans and vegetarians), allergies or health restrictions.

We have a DGD with allergies to nuts and salmon, both of which foods have been staples in our Christmases. We have decided that the salmon is dispensable, as are a bowl of nuts, I can make my own nut-free puddings, cakes and mincemeat that tastes just the same but when I planned a venison casserole without chestnuts, even DS and DDiL looked horrified. So I made a venison stew, without the chestnuts, then put portion for DGD aside and added mushrooms and added chestnuts to the rest before freezing them.

Much of the Christmas meal vegans and vegetarians can eat: roast potatoes, all the vegetables, stuffing. A Christmas pudding, probably acceptable to all, can be made using veg suet and egg substitute. After that you make accommodation - a nut roast, one portion of vegan 'cheese' and some vegan chocolates.

I would take both children firmly aside before the event and tell the vegan the adaptions you are making and make it clear that her principles are her principles and you will respect them, but she has no right to impose them on other peopel, if she wants to sulk on Christmas day, no one will take any notice of her, then tell her brother that he is not to goad her in any way, in word or deed. Just eat his meat and keep quiet.