Step 1

Preheat your oven to 350 degrees Fahrenheit.

Step 2

Grease a 9-inch by 13-inch baking dish with the butter.

Step 3

Add the apple chunks, mixed berries, sugar and cornstarch to the baking dish and toss with a wooden spoon until well combined and the cornstarch and sugar are coating the fruit.

Step 4

In a medium bowl, add the white and brown sugar, the oats, the flour, the cinnamon and the salt and stir well come combine.

Step 5

Add the melted butter and stir until well combined.

Step 6

Pour the topping evenly over the fruit mixture in the baking pan.

Step 7

Cover with aluminum foil and bake for 20 minutes at 350 degrees Fahrenheit.

Step 8

Remove the aluminum foil after 20 minutes and bake for an additional 20-25 minutes, or until the topping is golden brown and the fruit filling is bubbly.

Step 9

Let sit at room temperature for about 5-10 minutes before serving with vanilla ice cream.