Preheat your oven to 160°C for a fan oven (170°C for a conventional oven).

Cut the peaches into chunky slices and place them in a bowl. Add the raspberries and toss with the caster sugar. Transfer the fruit mixture to an ovenproof baking dish and set aside.

In a large bowl, mix together the flour, baking powder, and caster sugar. Using your fingers, rub in the cold butter until the mixture resembles coarse crumbs with pea-sized pieces of butter. Add the milk and mix until the dough comes together with a texture similar to soft cookie dough.

Spoon the cobbler topping over the fruit in the baking dish. Sprinkle with demerara sugar (optional) and the flaked almonds.

Bake in the preheated oven for 25-30 minutes, or until the fruit is juicy and bubbling around the edges and the cobbler topping is golden and fluffy.