To begin you'll need a large pot to boil water, and a large bowl full of ice and water. The first step is to blanch the peaches to remove the skin more easily. Bring water to a boil, and score each peach with an 'X' on the bottom. Put in as many peaches as will fit in your pot, and boil for around 3 minutes till the skin starts to peel back on its own.
Remove from the boiling water and immediately put them into the ice bath to shock the peaches and stop the cooking process. Repeat with all the fruit.
Once the peaches are cool to the touch you can remove the skin by peeling gently with either your fingers or the aid of a paring knife.
Cut peaches in slices and reserve in a bowl while you prepare the crumble topping. They will begin to release a good amount of juice that can be strained off and saved for your morning smoothie,( or Bellini!)
Pre-heat the oven to 350 degrees and gather a sheet pan lined with parchment to toast the quinoa. Spread on the pan and toast for 6-8 minutes, stirring mid-way till it is lightly browned. Here I'm using a combination of red and regular quinoa. Allow to cool then use a spice/coffee grinder to process into a fine flour. Save the pan to use in the next step as well.
Combine all the dry topping ingredients in a large bowl, slowly drizzle in the melted coconut oil and stir the mixture till evenly moist. Spread mixture back on the lined sheet pan and toast for 6-8 minutes till slightly browned and crunchy. Cool completely. You should have more topping than you will need for the dish. Save it for later in an air tight jar in the fridge.
While toasting the topping you can start cooking the filling. Heat the cast iron skillet over med-high heat, once hot add the drained cut peaches and the remainder of filling ingredients. As the cast iron is well seasoned, you do not need any additional fats/oils to cook with. Allow filling to come to a boil, then reduce the heat and allow to simmer for 12-15 minutes. The juices will thicken slightly and the peaches will soften. Try to refrain from stirring too much to maintain the integrity of the fruit.
Increase the oven temperature to 375 degrees. Remove the cinnamon sticks from the filling mixture and while still hot, distribute the cooled crumble topping evenly across the pan. Put the skillet, uncovered into the oven and bake for 20-25 minutes. Check mid-way through and rotate if the topping is browning unevenly. If the crumble is browning too fast, you can cover it loosely with foil, but be sure to allow the steam places to vent or you'll have a soggy crumble!
Remove from the oven and allow to cool for at least 15 minutes. This allows the natural pectin in the peach filling to set more completely and for the crumble to achieve that awesome crunchy texture.