Campfire Cobbler

Ingredients

• 3 c. sliced peaches (if using frozen peaches, thaw and drain first) -
• 2 c. raspberries -
• 1 c. blackberries -
• 3/4 c. granulated sugar -
• 3 tbsp. cornstarch -
• Juice and zest of 1/2 lemon -
• 1 tsp. pure vanilla extract -
• Pinch kosher salt -
• 1 c. all-purpose flour -
• 2 tbsp. granulated sugar, plus more for topping -
• 2 tsp. baking powder -
• 1/4 tsp. kosher salt -
• 1/2 c. (1 stick) butter, cold, cut into 1/2" pieces -
• 1/2 c. buttermilk -
• Vanilla ice cream, for serving -