Preheat your oven to 350°F (175°C). Grease your baking dish lightly with butter. This helps prevent sticking and gives a golden crust. Keep the dish ready for layering the cobbler mixture later.

Wash fresh blackberries gently under cold water. Pat them dry using a paper towel. Place them in a bowl and add sugar, lemon juice and cinnamon. Mix softly so berries stay whole and juicy.

In a separate bowl, mix flour, baking powder, salt and sugar. Slowly add milk and vanilla extract. Stir until smooth batter forms. The texture should be slightly thick but pourable and creamy.

Pour melted butter into the baking dish. Spread it evenly across the bottom. This step gives the cobbler a rich flavor and crispy golden edges during baking.

Gently pour the batter over the melted butter. Do not stir. The layering is important for the classic cobbler texture. It will rise around the fruit while baking.

Spoon the prepared blackberries over the batter evenly. The fruit will slowly sink while baking. This creates juicy pockets of sweetness inside the cobbler.

Place the dish in the oven and bake for 35 to 40 minutes. The top should turn golden brown. The berries will bubble and create a rich aroma in your kitchen.

Remove from oven and let it cool for 10 to 15 minutes. Serve warm for best taste. The cobbler becomes thicker as it rests and sets.