Preheat oven to 350 degrees. Butter inside large baking dish.
Combine apples, pears, 1/4 cup sugar, 1/2 cup brown sugar, and 2 tablespoon flour together in a large bowl. Mix until fruit is fully covered in sugar mixture.
Using a stand mixer combine the remaining of the ingredients. With the paddle attachment mix on low until it forms a crumbly mixture.
Place apples and pears into baking dish. Sprinkle the oatmeal mixture on top.
Bake for 1 hour.
Remove from oven and serve with vanilla ice cream.
Notes
I used a combination of gala and honeycrisp apples and bartlett pears. But use your favorites!