Warm blackberry cobbler with juicy berries under a golden, buttery topping is a rustic family dessert. This comforting classic is best served warm with a generous scoop of vanilla ice cream.
Preheat your oven to 375°F (190°C) and place the unsalted butter in a 9x13-inch baking dish; let it melt while the oven heats.
In a large bowl, combine the blackberries, half of the sugar (½ cup), and lemon zest. Toss gently and set aside for juices to develop.
In another bowl, whisk together flour, baking powder, salt, and remaining ½ cup sugar. Mix in the milk and vanilla extract until a smooth batter forms.
Remove the heated baking dish with melted butter from the oven. Pour the batter evenly over the butter—do NOT stir. Then spoon the blackberry mixture and juices evenly over the batter—again, do not stir.
Bake for 40–45 minutes until the cobbler is golden brown and bubbling at the edges. Let cool for 15 minutes before serving to allow the juices to thicken.