Slice peaches in thin slices. Sprinkle the peach slices with maple syrup, lemon juice, vanilla, cinnamon and arrowroot powder, then gently mix to coat peaches. Bake the peaches covered with foil for 40 minutes.
While the peaches are baking, into a mixing bowl add wet ingredients and mix. Into the wet ingredients, add oat flour, oatmeal, and coconut. Stir to combine.
Crumble the oatmeal cookie topping over the baked peaches in an even layer. Bake the Crisp uncovered for 20 minutes.