In a medium skillet, combine 2 cups of blackberries, 1 cup of granulated sugar, 1 cup of water, 2 tablespoons of lemon juice, 1 teaspoon of ground cinnamon, and 1 teaspoon of vanilla extract. Heat over medium heat until the mixture begins to simmer, stirring gently to dissolve the sugar and incorporate flavors. Allow this delightful blackberry sauce to bubble for about 5-7 minutes until the berries soften and release their juices.

In a large mixing bowl, whisk together 2 cups of flour, 2 tablespoons of baking powder, 1 teaspoon of ground cinnamon, 1 teaspoon of salt, and 1/4 cup of sugar. Using a pastry cutter or your fingers, cut in 1/4 cup of cold unsalted butter until the mixture resembles coarse crumbs. Gradually stir in 3/4 cup of buttermilk and 1 teaspoon of vanilla extract until the dough is just moistened but not over-mixed.

Once the blackberry sauce is bubbling, reduce the heat to low. Using a tablespoon, drop small dollops of dumpling dough (about 1 tablespoon each) into the simmering sauce, ensuring they are spaced slightly apart. Cover the skillet tightly with a lid and let the dumplings cook for 12-14 minutes, avoiding the temptation to lift the lid. The dumplings should be fluffy and cooked through, reaching an internal temperature of 195°F.

After the dumplings are cooked to perfection, allow them to cool slightly for about 5 minutes before serving. Gently spoon the warm Blackberry Dumplings into bowls, ensuring each serving is topped with a generous amount of the sweet sauce. For an indulgent touch, add a scoop of vanilla ice cream or a dollop of whipped cream on top, making this comforting dessert even more delightful.