Blackberry Pecan Cobbler

First, preheat your oven to a high temperature of 400 degrees Fahrenheit (200 degrees Celsius).

Then, combine the blackberries with a generous amount of 1 cup sugar in a large saucepan. In a separate bowl, mix the cornstarch with cold water until smooth, and then add it to the berry mixture. Place the saucepan over medium-high heat and bring the mixture to a boil, stirring constantly until it reaches a bubbly consistency and thickens, taking around 3 to 5 minutes.

Next, transfer the blackberry mixture to a 9x13-inch baking dish and set it aside for now.

Now, in another bowl, whisk together the flour with 1/2 cup sugar, baking powder, cinnamon, and salt until well combined. Using a pastry cutter or your fingers, work the cold butter into the dry ingredients until you achieve a crumbly texture. Stir in the chopped pecans, oats, and brown sugar until everything is evenly blended.

Add a splash of hot water to the mixture and stir until it's evenly moistened. Using a spoon, drop small amounts of the batter over the blackberry mixture in the baking dish.

Finally, place the baking dish in the preheated oven and bake until the top is golden brown and the berries are bubbly, taking around 25 minutes.