Remove pie crust to soften a bit, and if using frozen peaches take those out of the freezer and let thaw. If using canned fruit pour into a colander to drain liquid. Fresh needs pits to be removed and sliced. Roll out pie crust and press into pie plate.
In a bowl, toss your peaches gently with cornstarch. Add sugar, brown sugar and cinnamon. Combine. Pour the peach mixture into crust.
In a separate bowl, combine the ingredients for your crumble topping. Spread the mixture over the top of your peaches. Cover the pan with aluminum foil, place the pan on a large baking sheet (for any spillage), and bake at 375 degrees F for 30 minutes.
Remove the foil and bake for an additional 20 minutes, or until the crust is golden brown and the cobbler is bubbling. Carefully remove from the oven and let sit for 5-10 minutes to solidify a bit, then serve with ice cream.