Preheat oven to 375ºF. Lightly butter 10 individual oven-safe bowls OR an 8 x 8 inch OR 2-quart glass or ceramic baking dish.
Wash all the fruit and hull and quarter cut the strawberries.
Combine strawberries, blueberries, raspberries, 3 TBSP sugar, 2 TBSP flour and 1/2 TSP cinnamon in a large bowl. (NOTE: You could add blackberries too if you like them!) Evenly divide the berries between bowls or transfer to prepared baking pan.
TOPPING
Mix oats, sugar, flour, cinnamon and salt in a large bowl. Add butter and work into dry ingredients with a wooden spoon or pastry cutter until mixture is crumbly. Sprinkle oat mixture evenly over berries.
Bake 35 to 45 minutes for baking dish (or 20 – 25 minutes if individual bowls!) or until berries are bubbly and topping is lightly browned and crisp.