Don't make 2 meals! 

What I have always done for my kids is- like it or not, you will take 3 bites. When they were little we called them "No thank you bites"- you can say no thank you after the 3rd bite and go make yourself a sandwich. 

Keep something she likes on hand that she can make herself but make her sit and try what you make first. She might get up every singe time to make her dish, but at least she is trying something new. She may find that your stuff isn't so bad eventually. 

have Dad cook on her days at his house and let him handle the fall out. Your kiddo can pick a different day for her requests. 

How frequently does SD stay with you all? It's pretty infrequently, right, since she is long distance?

There are a couple different ways to address this. First is to make sure that meals include something that SD likes. Most of her diet is dictated by someone else not in your household, so it's not that odd that she isn't acclimated to your family's tastes. Additionally she is younger, and if she hasn't been exposed to much on a daily basis, her palette is going to be limited. A few weeks a year with you all isn't likely going to change that.

So, make sure each meal has at least one thing she'll eat. Make sure she has access to other foods that she can grab and eat or make on her own (or with the help of her dad). Also rotate in meals that she'll eat into your weeks. It doesn't have to be every meal, of course, but maybe rotate it so one night is something you and DH want, one is a meal SD wants, and one is a meal DD wants.

If SD complains even if you make her something she likes, then your DH earns himself the title of Chef for ALL her meals. You and DD keep making meals as you would, but DH takes on feeding SD. Sure, it'll be two meals, but that's his problem to deal with as her parent, not yours.

I always gave my kids one no.  There was one food they didn't have to eat.  Maybe it was tomatoes? Onions?  After that it was eat what you're served and there will be no treats or desserts for people who don't eat fruit/veggies.  It's so easy for a child to get stuck in the world of chicken nuggets, hotdogs and fried foods that any fruit, veg or different meal becomes a challenge.  But unless you're cooking wildly different food it shouldn't be impossible.  Make sure that dinner involves something plain and something interesting.  I hate foods drowning in cream sauces and garlic.  But I'm happy to serve the same dish that everyone else is eating and pulling aside some of the dish to serve plain.  My SD hated tomato sauce, but was quite happy to have her spaghetti plain with butter, and then the ground beef or meatballs and veggies on top of that.  I wouldn't let her get away eating plain buttered noodles. But I was happy to keep some of the ingredients separate for her to build it as she saw fit.

I like taco night or pizza night with the kids.  Choose one protein (chicken or beef), choose two veggies (salsa? green peppers? onions? or a side of carrots?) chose one grain (tortilla? corn shell? crackers?) and one dairy (cheese? sour cream? ranch dressing? glass of milk?).  It was all put out in bowls and we just made it "our way" at the table.  It felt less like making two meals and more like accounting for individual preferences.  But nutrition was still a requirement.

As for your daughter feeling overruled, if you give them each a day to pick a favourite meal it might be more fair?  It's not fair to your daughter to have a long stretch of food she doesn't like. Nor is it fair to your SD to do the same.  Perhaps each gets one day a week to pick a fav meal, and the rest of the week you try to find common ground.

ok. I just went back a bit and see that your SD is not with you for meals often as she lives out of state w/ her mom. so most of your meals don't even include her. this shouldn't be a big deal. your daughter can pick year round what she wants for meals she is hardly being overruled.  

when SD is there perhaps it's best if Dad cooks/meal plans and yes, SD should get some say in it but not total say every day of the little time she's actually there. 

But really, your daughter shouldn't be a part of this equation. she is there picking meals all the time. SD is not. of course those few times SD's there she should get a say. 

I have this problem with my SD's. They only eat Mac n Cheese, potatoes, and beef. I used to knock myself out making healthy meals with veggies and fruit on the side, but they turned up their noses at it, so now DH makes all their meals. Sometimes they insist on takeout, and he obliges them. So, those nights I make myself dinner, as I am watching my salt intake. It works for me, because then I don't have to wait on them to get their lazy butts over to our house before 8 pm. 

I THINK I HAVE MILD PSTD FROM FOOD ISSUES. Seriously. You can go back and read my blogs. Food issues CONSTANTLY from the time the SDs were 7 and 9. YSD is not ALMOST 17 and STILL FOOD ISSUES.

1) I first stopped helping at all with school lunches when OSD was 10. She refused to eat her lunch, only snacks that were packed. Then I packed a lunch with ONLY snacks and she also complained. Told DH he now gets to do it. Within two weeks she was making her own lunch.  YSD naturally started doing her own lunch around age 10.

2) Around the same time I put a kibbosh on making two meals. NOPE NOPE NOPE. DH could do so if he cooked, but I wouldn't help in any way. No cleanup, nothing. If I cooked, one meal only which was a huge challenge since the SDs had not been exposed to anything much at all (bread, white rice, plain pasta, chicken strips, chicken nuggets was seriously the entire diet). Until they met me they never even had eaten a fresh cherry!  I had to teach them how and abuot the pit - astounded!

3) As OSD got older, and did not grow out of her issues, I refused to cater to her at all. I cooked what DH, YSD and myself all liked, making sure that there was at least one nutritiuos thing on the table OSD would eat. Eventually she started even refusing that. So I told DH - then SHE COOKS HER OWN FOOD. And I was out. Drove DH crazy because he wanted everyone to eat together so OSD would be cooking at the same time, in his way, which he hates. He tried making things himself for her - which of course she refused (age 13) with yelling and tears. FFS.  Nightmare. Sometimes I would just get up and leave the table. 

4) YSD was a good eater for a long time, but has since regressed. So I told DH the same thing I did about OSD. I was not helping. DH is a little more patient now, but if YSD is with us more than a couple nights, it does cause issues. But I ignore. If I feel like making a particular meal she won't eat I let DH know early in the day so he can help her figure things out. AT ALMOST 17. 

There's a mindset that goes with this accommodating behavior of you OP.  Skids seem to relish the control it gives them.  Most of it ends up negative behaviors from them.  Some kids just like being the PITA.  If you want her feel a part of the family, then you put YOUR limits around food prep in place and you don't make anyone feel "special".   If you don't buy junk food normally, you don't just when she is there.  She is nine. If adults set the tone for the home then  the kids follow the rules, not make them.   Do you like having a nine year old puppet master in your midst?  That's why you are so angry.  Take back your control over this.  You got some great suggestions above.  Chose the easiest for you to live with, put everyone on notice at the next family dinner time and don't bend on it.   Food can be a real source of fights if you let it.     Your choice.  

I guess Im lucky because SD16 SPMS eats everything. Shes on the heavier side. Just no activity of note.

Honestly what the heck is wrong with these children? Is it a power game, is it a difference in palate, is it the neurodivergence?????

If we didnt want to eat something prepared by our family, we went hungry!

What was put in front of us or go hungry.   Truly hungry kids aren't picky eaters.  #oldschool.

Of course with the realization that BM is in the picture and hanging on every move to report as "child abuse."

Oh god this is such a pet peeve of mine. Especially with other adults, the whole picky eating thing lol I can understand not liking a couple things. Like olives or something. But my friend who doesn't like cucumbers, cherries, any vegetables, mushrooms, I tell her she can provide the pupus for pau hana!

Totally unrelated rant by me so I apologize. My message is because of my irrational hate toward this I don't think I could offer any help, and I could use some myself! 

IMO, the stepkids food issues are a way for them to them to passive-aggressively rebel.  We had SDnow61 who never ate fish, fruit or most vegs.  We had YSSnow57 who turned up his nose at anything that was home-prepared.  Coincidentally, these were the two who liked me least.   Whatever.  The less attention paid to these foibles, the better.  I fixed the meal, they could eat it or whatever.

As a side note, SD61 is still picky and her health suffers from it.  YSS outgrew his early fast food addiction and now eats healthily.

SD can eat what is prepared or starve. Her choice.

We have always been very eclectic eaters.  SS included. The only deviation from that is mushrooms. Which is odd.  When he was a toddler he loved them.  Then when he was about 6 we were staying with my parents after we sold our home and before our new home was ready for move in.  

One night when we had sat down for dinner, mom had cooked, dad took a bite and then said.... "Are there mushrooms in this? I hate toad stools!"  This has been a back and forth banter between my parents my whole life.  

From that moment on SS never touched another "toad stool".  My DW still gives my dad crap about that, ~25 years later.  "You know he still won't eat mushrooms."  My dad just grins and chuckles at her. Then they go down their usual path of razzing each other for the next couple of hours.

Even after he chose to no longer like mushrooms, if they were part of dinner, he had not choice but to eat them or pick them out of the food. We did not cater to rediculous kid culinary demands.  Neither when something specific was demanded, nor when it was rejected.  You eat what is made or you starve.  Your choice.

He understood that. And still understands it.