I think it depends on the recipe. I've rarely found one that couldn't be doubled or the pan size changed (i.e. mini muffin vs. standard size) but occasionally some recipes don't double well. Most of the time that is due to the density of the batter--not allowing the ingredients to distribute as well as they might have in a smaller batch. I have one cookie recipe that is more chocolate chunks than batter and the one time I tried to double a batch I had dire results. If I do double the recipe I do it twice, mix it well, THEN combine the two batches and that works great. You don't want to overwork muffin batter because it will make the muffins tough so if your batch was very large you might work too hard to get it all mixed and toughen the muffins.
Mary B. So love your message concerning local people that tell you all the time about the Cho Cho and how they are missed. Looking forward to making a trip to that store in Temple PA. It is a long way to go for a Cho Cho wonder if they are as good as back in the 50's. Or maybe that Ice Cream Store ships going on line to find out. Thank's cuz for giving me this information.