In a large bowl, combine the berries, granulated sugar, and 2 tablespoons of flour and cinnamon.
Pour the berry mixture into a baking dish.
In a separate bowl, combine the oats, brown sugar, 0.5 cup flour, salt, and cold butter. Use your fingers or a pastry blender to cut the butter into the dry ingredients until the mixture resembles coarse crumbs.
Sprinkle the oat topping evenly over the berry mixture.
Bake for 35-40 minutes, or until the topping is golden brown and the berries are bubbly.
Let cool slightly before serving.
Notes
Serve warm with a scoop of vanilla ice cream or whipped cream.