How to Make It
Prepare the Filling: Preheat oven to 375°F. Butter an 11- x 7-inch baking dish.
Stir together berries, rhubarb, cornstarch, sugar, zest, juice, salt, ginger, and cardamom in a large bowl. Spread evenly in buttered baking dish.
Prepare the Topping: Pulse brown sugar, flour, butter, cinnamon, and salt in a food processor until clumpy. Add oats and almonds, and pulse until a coarse meal forms. Sprinkle topping evenly over filling.
Bake in preheated oven until bubbly and topping is browned, 35 to 40 minutes. Let stand 5 minutes. Serve with ice cream, if desired.