Preheat oven to 350F. Spray an 8x8-inch baking pan lightly with oil.
In a large bowl, toss together blueberries, raspberries, strawberries, sugar, cornstarch, and lemon juice. Pour into the prepared pan. Top with Honey Bunches of Oats with Almonds.
Bake in preheated oven for 25 minutes or until the fruit is bubbly. Serve warm with vanilla ice cream.