Preheat oven to 350°F (177°C).

In a medium bowl, combine the blackberries, ¼ cup sugar, water, and lemon juice. Stir gently to coat. Set aside.

Place the butter in an 8x8-inch baking dish or pie dish and place in the oven to melt. Watch the butter so that it doesn’t burn.

In a separate bowl, whisk together gluten-free flour, 1 cup sugar, baking powder, salt, and milk. Stir to combine.

Remove the baking pan with the melted butter from the oven and pour the batter on top of the butter without stirring.

Pour the berries mixture on top without stirring. The berries will sink to the bottom during baking.

Bake for 45–50 minutes, until the topping is golden and the filling is bubbling. Cover loosely after 25 minutes to prevent heavy browning if necessary.

Let cool slightly before serving. Enjoy warm with a scoop of ice cream if desired!