I can't find any picture for some reason.
It seems you want feedback so i'll give you that. From your description I'd find that too over the top. Why not just leave out the burger at that point? Duck liver, truffle and norwegian taleggio - put it on a really nice open face sandwich and leave it at that. I would find the meat to be distracting from the other flavors.
I also think that if you have some really good beef, why grind it up? I would prefer the beef not the hamburger from a really good piece of meat.
But then again, I don't much go for the super gourmet burgers that i've had. Main problem is they're impossible to eat without a fork and knife, and that kind of defeats the purpose of a hamburger. I'd concentrate more on having a really good roll, big enough and substantial enough not to fall apart in my hand, (maybe a choice of in-house-made rolls, some softer with milk in the dough and some crustier, some with other kinds of flour - and i generally like sweet kinds of additions to burgers, like red onion, and in particular pickalilli or bread and butter pickles, or onion marmalade, or other slightly sweet things. If it has cheese, it should be sharp enough to actually taste it.
Make sure to make the toppings yourself, not from a can or bottle. Like ketchup - i don;t particularly like ketchup on hamburgers, but i don't like any of the commercial ketchups at all - i prefer home made (tomatoes, dark brown sugar, good vinegar, basil, garlic, pepper, mustard, simmered and then blended.) Your own home made pickles - i like sweeter kinds, but you can make hot or sour kinds, home made dill pickles, or pickled or preserved peppers, onions, green tomatoes or green tomato picalilli (how DO you spell that?). Or grilled and then marinated eggplant slices.
Make sure to have a vegetarian version, based on something like a thick piece of grilled halloumi or a breaded and fried piece of cheese or thick breaded and fried eggplant slice. You exclude a whole group of people if one of them is vegetarian and you don't have any options for them - they'll go somewhere else if they're out together.
thanks for the input!
first of all, the kobe-burger was our input for a competition where the ready burger was provided by our sponsor. offcourse i share your opinion on grinding dry-aged kobe beef, personally i think this meat doesn't need the dry-aging....
all is made by myself at CulinaireZaken, i don't like the ready made pickles/sauces...
thanks for the vegetarian input!