Preheat oven to 350. Grease a 11×7, 9×9, or 8x8 dish.
In a large saucepan add the apples, berries, lemon juice, butter, brown sugar, cinnamon, nutmeg and vanilla. Bring to a light boil and let cook 1-2 minutes.
In a separate bowl mix together the oats, flour, brown sugar and chopped nuts. Add the butter and combine with a pastry cutter, fork, or your hands.
Add 1/2 cup of the topping mixture into the filling mixture, stir and put the filling in the prepared pan.
Sprinkle the rest of the topping all over the filling.
Bake at 350 for 50 mins.
Remove from the oven and let cool for at least 15 minutes before serving!