Old Fashioned Blackberry Cobbler

Melt Butter:Place the stick of butter into a 9×13-inch baking dish and put it in the oven to melt. Once melted, remove the dish from the oven.
Make the Batter:In a mixing bowl, whisk together flour, sugar, baking powder, and salt. Slowly stir in the milk until a smooth batter forms.
Assemble the Cobbler:Pour the batter evenly over the melted butter in the baking dish. Do not stir. Sprinkle the blackberries evenly over the batter, and drizzle with lemon juice if using. Optionally, sprinkle a tablespoon