Preheat oven to 350 F.
In a bowl stir together thawed and drained peaches and granulated sugar.
Stir flour into peaches until syrup has thickened. (may need more or less flour to thicken to your liking)
Using a slotted spoon, place peaches in a deep dish pie plate. (let the excess syrup drip off. See note). Set aside.
To make the toppings, in a separate bowl stir together brown sugar, granulated sugar, flour, oats, cinnamon, all-spice and salt until combined.
Cut in butter using your hands until mixture is crumbly.
Sprinkle topping evenly over peaches.
Bake for 35-45 minutes or until topping has browned and crisp. (May need longer)
Let crisp cool slightly to allow syrup to thicken, about 10-15 minutes.
Serve warm with a side of vanilla ice cream. Best served the same day. (Topping will not be as crisp the next day or when reheated.)