Step 1: Preheat the oven

• Preheat your oven to 375°F (190°C). Grease a 9×13-inch baking dish or a deep pie dish.

Step 2: Prepare the filling

• In a large mixing bowl, combine the blackberries, sugar, cornstarch, lemon juice, and vanilla extract. Toss gently to coat the blackberries evenly.
• Transfer the mixture to the prepared baking dish and spread it out evenly.

Step 3: Make the topping

• In a separate bowl, whisk together the flour, sugar, baking powder, and salt.
• Add the cold, diced butter and use a pastry cutter or your fingertips to blend until the mixture resembles coarse crumbs.
• Pour in the heavy cream and mix until just combined, forming a dough.

Step 4: Assemble the cobbler

• Drop spoonfuls of the dough evenly over the blackberry filling. It doesn’t need to cover the fruit completely; the juices will bubble through while baking.

Step 5: Bake the cobbler

• Place the dish in the preheated oven and bake for 35–40 minutes, or until the topping is golden brown and the filling is bubbling.

Step 6: Cool and serve

• Remove from the oven and let the cobbler cool slightly. Serve warm with a scoop of vanilla ice cream or a dollop of whipped cream.