In a large mixing bowl, combine the blackberries, sliced peaches, granulated sugar, lemon juice, and vanilla extract. Toss well and let it sit for about 10 minutes to allow the juices to meld.
In another bowl, whisk together the flour, baking powder, salt, ground cinnamon, and brown sugar until well combined.
In a separate bowl, mix the melted butter and milk together before adding to the dry ingredients. Stir until just combined but do not over mix.
In a large oven-safe skillet, pour the berry and peach mixture evenly across the bottom.
Spoon the batter over the fruit mixture, trying to cover it as much as possible.
Place the skillet in the preheated oven and bake for about 25-30 minutes, or until the cobbler is golden brown and a toothpick inserted into the batter comes out clean.
Once baked, remove the skillet from the oven and let it cool for a few minutes before serving.
Serve warm, optionally topped with a scoop of vanilla ice cream.
Notes
Serve warm with a scoop of vanilla ice cream for an extra treat.