I found it! After three or four attempts (I think I tried one a couple times), I finally found a cobbler recipe to save in my recipe file. My other attempts always ended up kinda mushy. Not untasty - it's still fruit and sugar with goodness baked on top of course - but not fabulous. This one is a keeper.
The topping is really what makes it - it's essentially like having a blueberry cake on top of a peach filling. Sooooo good. Love the addition of turbinado sugar on top to give it that extra crunch. Lessons learned - use peaches that are ripe but still firm, and adjust the amount of sugar depending on the sweetness of the fruit. If your peaches are on the tart side, the amount is just right, but if they're on the sweeter side, you may want to reduce the sugar a bit. Peaches and blueberries are in season, and having this for dessert every night this week is just one way I'm celebrating.