For the crust, mix all the dry ingredients in a large bowl.
Make sure coconut oil is hard. Cut it into small pieces, as small as you can, then add it to the dry ingredients. Mix and knead until you get a crumbly texture. Make sure all chunks of coconut oil are gone - squeeze them between your fingers and mix the oil into the flour.
Once you have that crumble, add oat milk to it, tablespoon by tablespoon. I start with 3 tablespoons and add more if needed. It depends on your flour, so pay attention to the texture of your dough. It should be pretty soft, but still stick together and hold the shape you give it. It shouldn't be too dry and it shouldn't be falling apart. Leave it on the kitchen counter.
For the filling, cut peaches into thin slices. I used 4 peaches, but if they're small you might need 5 of them. Slices should be 2-3 mm thick.
In a small bowl, mix together brown sugar and cinnamon.
Roll out your dough on the countertop. I usually place the ball of dough between two sheets of parchment paper and roll it out so there's no mess. But you can flour your surface and roll out the dough there. No matter what you do, you should roll it out into a pretty big circle. Take into account you'll be folding the edges in, so you have to leave a few centimeters of the dough around your filling.
Once that's done, move your dough onto a baking sheet. I use the big ones and move the dough together with the bottom parchment paper I use for rolling out the dough. This method really makes everything easier.
When the dough is placed onto the baking sheet, take your peaches and place them onto the rolled-out dough. You can make circles as I did, or place slices in any other way you like. Make sure that the filling is only in the middle and you spare a few centimeters of the edge all around the filling.
Once you're done with placing peaches, fold the dough in gently. Be careful not to tear it away at the bottom. It will crack as you fold it and create edges, but that's okay. You just don't want it to crack open at the bottom because then the juices flow out and burn while baking.
As you finish everything, take 10-20 ml of oat milk and a brush. Brush the milk all over the edges you folded in. Sprinkle the sugar and cinnamon mix all over the edges. Use the remaining mix to sprinkle over peaches.
Bake for about 30 minutes at 180°C. You want the crust to have a golden brown colour and peaches to be soft and golden.
Let it cool down a bit before cutting it. It's amazing with some vanilla ice cream or whipped cream.
