Preheat and Prepare: First, preheat your oven to 180°C (160°C fan). Lightly grease a 2-litre ovenproof dish or a 23cm cast-iron skillet.

Make the Peach Filling: In a large bowl, gently combine the sliced peaches, light brown sugar, caster sugar, lemon juice, cinnamon, nutmeg, plain flour, and a pinch of salt. Stir until the peaches are evenly coated.

Arrange the Filling: Pour the peach mixture into your prepared baking dish and spread it out into an even layer. Set it aside while you make the topping.

Mix the Dry Ingredients: In a separate mixing bowl, whisk together the 250g of plain flour, 100g of caster sugar, baking powder, and 1/2 tsp of salt.

Cut in the Butter: Add the cold, cubed butter to the flour mixture. Using your fingertips or a pastry blender, rub the butter into the flour until the mixture resembles coarse breadcrumbs with a few pea-sized lumps of butter remaining. I find that using my hands gives me the best feel for the texture.

Add the Wet Ingredients: In a small jug, mix the milk and vanilla extract together. Pour this into the flour and butter mixture and stir with a fork until just combined. Be careful not to overmix; a few dry spots are perfectly fine. The dough should be soft and slightly sticky.

Assemble the Cobbler: Drop large spoonfuls of the topping batter over the peach filling, leaving some gaps for the fruit juices to bubble up through. There's no need for it to be perfect; a rustic look is what we're after.

Bake to Perfection: Sprinkle the top of the batter evenly with the demerara sugar. This will create a lovely crunchy crust. Place the dish on a baking tray (to catch any potential drips) and bake for 40-45 minutes, or until the topping is a deep golden brown and the peach filling is bubbling vigorously around the edges.

Rest and Serve: Let the cobbler cool on a wire rack for at least 15 minutes before serving. This allows the filling to set up slightly. It's wonderful served warm.