I used raspberries rather than blueberries. Also- to avoid it being 'overdone' like I mentioned before, don't use frozen blueberries, and check it after 60 minutes
These are great! I made them twice; the first time I thought the muffin cups were starting to look too full so I did two pans of twelve each, which was a mistake — it worked much better to make a dozen and fill the cups completely. I also cut back slightly on the salt the second time and was a little more generous with the Nutella.
