In a bowl, combine blackberries, sugar, and lemon juice. Gently toss to coat the berries and set aside.

In a mixing bowl, whisk together flour, baking powder, sugar, and salt.

Add milk and melted butter to the dry ingredients and stir until just combined.

In a saucepan, combine water and sugar over medium heat until sugar dissolves.

Drop spoonfuls of the dumpling dough into the simmering water. Cook for about 10 minutes until they float to the top.

Add the blackberry filling on top of the dumplings and cover. Cook for an additional 10-15 minutes until the dumplings are cooked through.

Remove from heat and let cool slightly. Serve warm with additional blackberries if desired.