Get a medium fire going - you can cook this over a campfire, hot coals, or on a grill.

In a medium bowl, combine granola, sugar, oat flour, and nuts, if you’re using them. Add melted butter, stir until well incorporated - everything should be wet, but crumbly.

Add the topping to a 9" cast iron skillet, toast over the hot coals until golden brown. Transfer to a bowl, set aside.

Melt the butter in the 9" skillet. Add the peach slices, ¼ cup of the sugar, and the lemon juice.

Lower the heat of your fire or grill, cook for 5 minutes. Add the blueberries and water, simmer for another 5 minutes.

Mix together the remaining sugar with the cornstarch and salt, sprinkle over the fruit mixture. Add the vanilla extra, stir well to combine.

Cover and cook - gently stirring every so often - until the juices have boiled down to a thick sauce, and the filling is the texture you want.

Sprinkle the granola mixture evenly over the top of the berry filling.

Cover skillet with a tightly fitting lid - or some aluminum foil - and allow to sit off the heat for 2-3 minutes before serving.

Serve hot, with a scoop of ice cream or mound of whipped cream, if desired