Pre-heat oven to 400 F.
Lightly spray 4 to 6 individual baking dishes (mini cast iron skillets are best) with nonstick cooking spray. Set aside.
In a food processor, pulse together 1/2 cup flour, graham, cracker crumbs, oats, butter, brown sugar, cinnamon, nutmeg, and salt until crumbly (don't over process, make sure it's good and crumbly). Set aside.
In a medium bowl, stir together peaches, blueberries, blackberries, and vanilla.
In a small bowl, combine sugar, remaining 2 tablespoons flour, and cornstarch and sprinkle over fruit, stirring to combine. Let stand for 10 minutes.
Divide fruit among prepared dishes and then sprinkle with oat mixture.
Bake 25 minutes. Check after about 15 minutes, and if starting to brown, cover with foil.
Let cool on a wire rack for 10 to 15 minutes.
Serve with ice cream.