Heat oven to 375 degrees.

Place the sliced peaches, sugar, cornstarch, and lemon juice in bowl. Toss to coat.

In small bowl, mix the oats, flour, brown sugar, and cinnamon. Cut the butter into pieces and add to the oat mixture. Use your fingers and mix until a crumble forms.

Place half the peach slices in the bottom of the baking dish. Pour the frozen berries on top of the peaches. Layer the remaining peach slices on top of the berries.

Sprinkle the crumble topping over top of the peaches.

Bake for 25 minutes or until crumble is melted and starts to bubble.

Remove from oven and serve hot.