I realize these are summer fruits, and both the higher cost and lesser availability of these fruits might be a disincentive for some of you. Frozen berries are a great option here. Fresh blueberries were oddly enough the most expensive of the three berries, so I bought frozen blueberries and fresh raspberries and blackberries.
Preheat oven to 375 degrees F.
Mix topping ingredients together, stirring in the melted butter last, and set aside.
pie dough by premade Wegmans (If you’d rather make your own crust, go nuts)