I thought of a couple of you when I saw this. This is not so much "made-to-order" but specialized cooking, THE MUFFIN BAR I call it.
I thought, here is the mix and you can ask the guests what ingredients they want in their muffins, or even let them choose them from a fruit /nut chocolate bar (if you had a couple rooms). Just like you who do smoothies might ask (sorry the graphic is small hit CTRL+ to enlarge the screen on your browser) just imagine anything that could go into a muffin on the list (on "the muffin bar"):
I thought, here is the mix and you can ask the guests what ingredients they want in their muffins, or even let them choose them from a fruit /nut chocolate bar (if you had a couple rooms). Just like you who do smoothies might ask (sorry the graphic is small hit CTRL+ to enlarge the screen on your browser) just imagine anything that could go into a muffin on the list (on "the muffin bar"):