Preheat the oven to 375 degrees F.
To make the topping place the oats, flours, almonds, wheat germ, brown sugar, cinnamon, nutmeg, and salt in a food processor and process until well combined.
Add the butter and oil and pulse until lumps form.
Add the water 1 tablespoon at a time until the dough just holds together when you press it between your fingers.
Transfer to a bowl and using your fingers, press the dough to create several pea-size lumps for texture.
Chill until ready to use.
To make the filling, leaving the peels on, core and cut the apples into 1/4-inch-thick wedges.
Toss the wedges with the lemon juice and maple syrup until well coated.
Sprinkle with the flour and toss until well combined.
Spoon the apple mixture into a 3- to 3 1/2-quart shallow baking dish and sprinkle the dough evenly over the top.
Bake in the middle of the oven until bubbling, the apples are tender, and the topping is golden brown, 45 to 50 minutes.
Serve with the vanilla cream topping, if desired (see recipe below).