Preheat oven to 400°F.
In a coffee grinder (works best, but you could also use a food processor) combine the ingredients for the pistachio parmesan and grind into a fine meal. Set aside.
Thinly slice the sweet potato and onion with a mandolin. Coat with 2 teaspoons of olive oil and set aside.
Massage lemon juice into roughly chopped kale and set aside.
To make the crust, blend together 1 ½ cups of all-purpose flour, rosemary, sea salt, and ground black pepper in a large mixing bowl.
Using a pastry blender, cut in pieces of the solid and cold coconut oil until the mixture looks like crumbs. Make a well in the middle of the flour mixture and add cold water. Fold it only a few times with your hands to mix the dough until it just comes together. Be careful not to over mix.
Lay out a large piece of parchment paper onto a flat dry surface. Dust the parchment paper with some of the remaining ¼ cup of all-purpose flour and place the dough on top. Rolling the dough out on parchment paper makes transferring it to a baking pan much easier! Dust a rolling pin with flour as well and gently roll out the dough to approximately a 15-inch oval or circle. It doesn’t have to be perfect as this is meant to look rustic.
Sprinkle about ¾ of the pistachio parmesan mixture on the entire surface of the dough.
Slightly overlap the thinly sliced sweet potatoes in the centre of the dough, leaving a 2-inch rim of dough all around.
Add a little more pistachio parmesan on top, then add kale, onion slices, and then remaining thinly sliced sweet potatoes (you might only use ¾ of the sweet potato depending on its size).
Fold the 2-inch edge of dough over top of the vegetables and pinch together any excess creating a crust. Take 1 tablespoon of olive oil and brush the edges of the crust with it and drizzle any remaining oil on top of the vegetables. Then sprinkle the remaining pistachio parmesan all over the crust and on top.
Lift the sides of the parchment paper and gently place the galette on a large baking sheet or pizza pan. Bake for 25 minutes.