Toss together the berries, lemon juice and 1/3 cup sugar in a large bowl. Pour into a 9x9 baking dish.
For the Topping:
Wipe out the large bowl. Add the cold butter, 2/3 cup sugar and flour into the bowl. Use your fingers or a pastry cutter to combine the ingredients to form a coarse crumble topping. Sprinkle evenly on top of the fruit in the baking dish.
Bake for 30 minutes, or until bubbly and crust is starting to turn golden on the edges. Let set for 5 minutes before serving. Optional: Top with a couple of scoops of vanilla bean ice cream.