A bubbling mixed berry cobbler with a golden crust over juicy seasonal berries is a vibrant family dessert. This versatile, easy recipe works beautifully with any combination of fresh or frozen fruit.
Preheat your oven to 350°F. Place the 6 tablespoons of unsalted butter into a 9x13-inch baking dish and melt it in the preheating oven; remove as soon as melted to prevent browning.
In a large bowl, toss the mixed berries with 1/4 cup of the granulated sugar and the lemon zest to evenly coat the fruit and draw out some juices.
In a separate bowl, whisk together flour, the remaining 3/4 cup sugar, baking powder, and salt. Stir in the milk and vanilla extract just until combined—do not overmix.
Pour the batter evenly over the melted butter in the baking dish, but do not stir. Spoon the sugared berries and juice evenly over the batter. Let the batter ooze up around the fruit naturally.
Bake for 45–55 minutes, rotating the dish halfway through, until the cobbler is golden brown on top and bubbling at the edges. Cool on a rack for at least 15 minutes before serving to set the juices.