From the Barefoot Contessa at Home cookbook, Tri-Berry Muffins!
It turned out great! Relatively easy to make also--the main berries were strawberries (chopped), blueberries, and raspberries. The only thing was, I thought I put the oven temperature for 375, but apparently, I actually put it on 325. Whoops.
So I'm not exactly sure how that affected the muffins, but for next time, I'll definitely make sure to double check. And probably put a little less sugar. And butter. Try to at least make it a bit healthier. :)