Preheat oven to 375 F°. Prepare a 9x13 casserole pan, lightly brush with oil and set aside.
Peel the peaches, if you desire(I left the skin on mine). Remove the pit, slice peaches into thick slices and place into a large bowl.
Toss peaches with sugar and cornstarch, transfer peaches to the casserole pan, spread evenly, and set aside.
In another bowl, combine brown rice flour, almond flour, sugar, baking powder, and salt. Mix well.
Add butter and mix until pea-size crumbs are formed. Add water and mix until the dough comes together.
Loosely drop the batter on top of the peaches. Bake for 40-45 minutes or until golden brown.
Serve warm with a scoop of vegan vanilla ice cream.