Fruit crumble

I volunteered to make dessert for Memorial Day. My friend Izzi, baking extraordinaire, suggested a crumble. It turned out well; simple, not overly sweet, and altogether quite delicious.

Filling (sauteed with butter in a saucepan, berries release their juices, etc.):
granny smith apple (tart!)
blueberries
strawberries
brown sugar
a little lemon juice

topped with granola, baked for about 35 minutes at 350.
served with a scoop of ice cream; I might do sorbet next time.