I think using real food during roleplay to represent the fictional food being served at a Tavern, an Inn or a camp during a campaign would help with immersion. Books like the Heroes' Feast books or Puncheons and Flagons would work as well as the Juniper's Companion to Venturesome Cookery blog or other fantasy-themed cookbooks like both volumes of the Elder Scrolls cookbook and the Diablo cookbook and cocktail book or the Warcraft cookbooks, you may have to rename some of the recipes though for the sake of roleplaying.

For example if you're doing a campaign set in Maztica you can make Maztican Pan-Fried Corn Fritters, Maztican Bean Stew and Mayzcakes(all from the Juniper's Companion to Venturesome Cookery blog), Argonian Swamp Shrimp Boil (from the first volume of the Elder Scrolls cookbook), Savory Thorn Cornbread (from the Elder Scrolls cookbook volume 2) and Kaeth (from Heroes' Feast: Flavors of the Multiverse). You can rename the Argonian Swamp Shrimp Boil and the Savory Thorn Cornbread to something like Tabaxi Shrimp Boil or Maztican Cornbread.

If you're resting in a tavern in the Domains of Dread you can serve Barovian Butterscotch Pudding from the first Heroes' Feast book along with the various Ravenloft foods presented in the second Heroes' Feast book as well as The Necromancer and Hand of Vecna cocktails (from Puncheons and Flagons) you can rename them to something like The Lich or Finger of Death.

If you're at a Tiefling Camp then maybe you can serve Fire-Spiced Abyssal Chicken Kebabs (from Heroes' Feast) and the Hellish Rebuke cocktail (from Puncheons and Flagons) along with Sheogorath's Strawberry Tarts (from the first Elder Scrolls cookbook) and Sanguine "Shaven Fruit" (from the Elder Scrolls cookbook volume 2). If you're hanging out with Aasimar you can serve Bytopian Shepherd's Bread (from Heroes' Feast) and Fargrave Sweetrolls (from the Elder Scrolls cookbook volume 2) with the Astral Plane cocktail (from Puncheons and Flagons). A Dragonborn camp can serve Arkhan the Cruel's Flame-roasted Halfling Chili (from Heroes' Feast) along with Dragonberries (from Puncheons and Flagons).

If you're at a tavern in Droaam maybe you can serve the Pack Leader's Bone Broth, Troll Fat Jerky (both from the second Elder Scrolls cookbook), Orc Bacon (from Heroes' Feast) and the Ogretoe cocktail (from Puncheons and Flagons).

It's an idea, whether it's good or not depends on a lot of variables. Cooking is a lot of work and it has time constraints that could be disruptive to actually playing. You're not gonna be able to pay attention to both cooking a meal and DM'ing your game, something you'd have to do if you want the players eating the tavern meal to line up with them RP'ing being in the tavern. Then there's the fact eating itself is quite an occupying task and could disrupt the flow of the game (which is why snack food is more popular during D&D games, especially low mess snacks).

Then you have dietary concerns which can put a spanner in the works. It's hard to do a tavern meal of crusty bread, drumsticks, and ale if one of your players is celiac, one is a vegan, and another doesn't drink. (I'm not being hyperbolic, that's literally one of my tables and I myself am two of those).

What you're describing is a lot of work for relatively little return as far as immersion goes.

What I would do instead is either

1. Serve D&D themed food before the game night to get everyone in the mood, or
2. Have a D&D themed dinner party separate from actually playing

By putting focus on the food rather than splitting the focus between preparing food and running the game, you can give both the respect they each deserve. If you're not tying yourself to an in-game theme, you have more flexibility on what you can serve. 

Overall, cute idea in theory, falls apart in the execution.

I was thinking the food could be prepared before the game and the food is eaten during a break period when the characters are resting in game. Also, you're right that in some groups, alternatives should be searched for.

It seems like a fun idea for the right group. As others noted, dietary restrictions would need to be followed. But otherwise, why not. 
I don’t think it would really do much for my immersion, but it’s easy to imagine people it would help. 

I think there might be a couple practical problems. Like having to put away all the books, dice, minis etc. Thenswap them for plates forks and knives, and then back again. 
And depending on the food and people, some folks might have a hard time getting back into gaming and instead be ready for a nap — I’ve played in a lot of sessions derailed by pizza. So with that in mind, it might work better to do after the game is done instead of in the middle. 

Serving food is a great idea, and having a ONE dish matching the theme is good as well.  But as mentioned, home cooked food usually minimizes dice rolling.  It is hard to care about some climatic scene when you and everyone else has meat juices (or non meat juices) running down the arm from a just grilled item.  

I will say besides the dietary restrictions already mentioned, some people like myself are just picky or nervous eaters and may not be too eager to try certain foods in a “different” environment. Sometimes I have a hard enough time just eating normal foods at games.  Even the smell might be off-putting to some. 

So, I wouldn’t try surprising the group with it, but instead bring up the idea and see who all is interested or if anyone is opposed.

Form the right groups, it can be really good. For others...not so much.

Personally, I tend to find food a distraction and a frustration. I don't like it at the table while playing because it tends to only slow things down while the player who just received the spotlight has to swallow an ill timed bite or whatever. I also tend to play without breaks, or if there is a break, it's just a short one to use the bathroom and maybe quickly refresh my head if the game has gotten a bit too heavy, so a couple of minutes at most. I also tend not to appreciate the food as much as the effort perhaps warrants? It's not something that gets me particularly excited, so basic food is perhaps better for me.

That said, other people are different. For them, having a themed meal afterwards would be amazing. If it's part of the understanding that you'll cook a meal afterwards, I would probably appreciate it as well, actually in that situation. The point is though, that different people appreciate different things. Whether it's a good idea depends on your skill as a cook...and whether your players are receptive to the idea.

As someone with misophonia for people eating, I can imagine few things that would be worse to add to a game. 

Honestly surprised at the amount of negativity on this thread.  At its core, D&D is about having fun with friends - and since the very dawn of human civilization, food and drink have been an established part of any social gathering.  Sure, you should take into account others' dietary restrictions, and, yes, of course you should make sure that your timing and prep does not distract from the primary event... but those are just core elements of Hosting 101, and problems folks have been quite capable of solving for the past few thousand years.

Speaking for myself, we always have food at our D&D games - there is always going to be a charcuterie board, a baked good, a cocktail, and perhaps a few other snacks.  I have done themed foods and cocktails before - many from the D&D cookbooks - and never once had players complain that there was an issue. As long as you know the basics of hosting (and, frankly, if you are having people over to your house, you probably should), there really should not be any problem.

So, I would say, if you think this is something that would improve your experience and be appreciated by your playgroup - and if you posted a thread like this, I expect that means you do think such - ignore the advice to the contrary you are receiving on this thread and go for it.  

I think maybe you're perceiving pragmatism as negativity. Almost every response has been "good idea, but keep X in mind" which is a constructive response to give considering the OP came in with a fairly solidly formed and supported pro-argument.

There's also the issue of where the game is being played: this might be easy to arrange at the GM's home, but not so much at a game store.  And could be outright banned if you meet some place like a library.

I was thinking in this case I would be the DM and the guy that makes the food. The game would preferably be at my home.

I'm not saying no, but a few things to keep in mind:

Prep time. Take all the prep time just on the day of that you normally need for a D&D session. Now find a couple hours for food prep time.

Playing space. Dice, character sheets, rolling trays, devices, etc. take up a lot of table space. Dishes, plates, silverware, etc. also take up a lot of table space.

Attention. People aren't good at multitasking. Juggling plates of food, dice, and character sheets might slow down gameplay. And somebody might accidentally swallow a D20, which would be super bad.

If you have the time and the energy to cook and to DM prep that's great! But maybe do food then D&D. Or do the food during a break in the middle of the session (maybe right after you set up the scene that inspired the cuisine).

I already said that I would serve it during breaks between scenes that set them up.

Quote from Samueltheslayer >>

I already said that I would serve it during breaks between scenes that set them up.

 But then don't you have one of two problems; either multiple extraneously long breaks making what is a long game longer, or serving food cold or otherwise unpalatable because you've prepared it in advance and let it sit?

We eat during play all the time, doesn't slow anything down. But its just food nothing special.

Now your idea would be great for one time thing during or after the campaign. The payers could even dress up as their characters for the event.

But for everyday play food. I would leave it to normal snacks and drinks.Everyone brings in something.

But its a fine idea. Run with it if you can.

I love the idea for a meal that coordinates with the adventuring party's food before or after the session, but I think most groups I play with would be distracted by any meal break and it would be at least an hour or two to get back to it.

That said, if you have the time, I love the idea of a dnd event-like weekend that would be breakfast - play all morning - lunch - play all afternoon - dinner.

I would suggest that you get one of the players, knowing the theme, to make the food.  Unless you're super excited about cooking, you're already shouldering a lot of the load.

Other than that, it's always a great way to bring in additional atmosphere.

I have done something a little simpler before, and it deemed 'neat idea with mixed results.'

Mine was "you all start in a tavern" and I served a beef stew or vegetable stew with a homemade bread and Root beer or real beer depending on preference. 
Turns out people preferred pizza, and i just said 'it was some halfling dish' after we got pizza hut, and i had a lot of Stew and bread left over.

this was also Pen and paper, so one reason people didn't want some foods is they were messy to eat and you don't want beef chunks on your sheet. 
I should have checked with the group first to see if they were even into the idea.

The final session the players requested I do it again, because the sheet were put away and it was just in character roleplay, but i couldn't so we went to a restaurant and just did in character talk. ( We did get some looks ) 

it can work, but it is A LOT of work and if you have people who aren't into it, it is wasted effort. Make sure you are all on the same page and check dietary requirements.