High Fantasy books nearly always have their characters eat the same things. Peasants eat breads with cheese, or simply dried breads, and royals are ALWAYS eating massive amounts of meats. In reality, it was not really like that.
For example, the peasants ate honey, fish, bread, ale, pottage, fruits and veggies, dairy, herbs, nuts, foraged foods, and occasionally meats(like cow, chicken, pig, sheep). There is a lot of foods that can come out of those ingredients; including things like pies. So, you should not just limit someone to bread and cheese, because they would have eaten more than that.
The most common food for peasants would for sure be pottage -which literally is just whatever you have on hand thrown into a pot- but even peasants had their festival foods.
My suggestion to writers is to come up with an ingredient list(or use the one I mentioned) to come up with recipes. For example, you could search “honey recipes” and look through them to find recipes that fit your list.
As for the rich people, they ate more than meat. Yes they did eat a lot more meat than the peasants, but they also ate other dishes too.
A documentary I greatly recommend watching is Clarissa and the Kings Cookbook. It follows a woman making recipes from a medieval-era cook book. One dish in particular in this cook book that might surprise you is “salads.” That’s right, kings were eating their veggies.
Rich people had the base amount of ingredients available to peasants, and more than that. They had the spices, the teas, and the wines, and all those other ingredients to make meals a lot more exciting.
They made gingerbread’s, they made salads, they made honey and wine broiled pears, and so on and so on…
The list of things that the rich people made is really big and amazing. So, you should not limit the nobles and the royalty in your novels to just meat on the bone, because that does not make sense.
I guess my whole point to this post is to say “please expand your imagination when it comes to food in your novels.” It never was as simple as bread and cheese for the peasants, and a hunk of meat for the royals, so think bigger.