Make the fruit base. Preheat the oven to 350°F (180°C). Then pit, peel, and slice the peaches. In a large bowl, toss together the peaches, maple syrup, arrowroot powder, lemon juice, vanilla, and cinnamon, until well combined.
Place in baking dish. Transfer the peach mixture to a 9 x 13-inch baking dish.
Make the peach crisp topping. In a medium bowl, whisk together the almond flour, coconut sugar, cinnamon, and salt. Using a pastry cutter or fork, cut in the butter until the mixture becomes crumbly. Then stir in the rolled oats.
Add the topping and bake. Sprinkle the peach crisp evenly over the sliced peaches in the baking dish. Bake for 35 to 40 minutes, until the peaches are bubbling soft and the top is golden brown.
Serve. Scoop a portion out and serve warm. You can also add a scoop of ice cream or whipped cream on top.