Move the oven rack to the bottom position in the oven. Preheat the oven to 350 °F (175 °C) and get out an 8"x8"x2.5" (or larger) baking dish (with or something similarly sized. It should be big enough to hold about 9 cups.

Prepare the topping. Mix together the dry ingredients in a medium bowl and then pour the oil, maple and vanilla on top. Stir until well combined. It will be VERY liquid at the beginning but will quickly firm up and by the time the filling is ready, it'll be as firm as a wheat-based crumble topping.

In a large mixing bowl, stir together everything except for the fruit. It may be a little lumpy and that's okay. Stir in the fruit and coat in the liquid mixture.

Pour the fruit onto the bottom of the ungreased pan and top with the topping. Pat the topping down a bit to make there that there aren't any pointy bits (if any little bits are sticking out a lot more than the others, they'll burn). If you think there's any chance of the fruit bubbling over, place the baking dish on a baking sheet before putting in the oven.

Bake for 40-45 minutes or until the filling is bubbly around the edges.

Let cool for at least 2 hours. The sauce will thicken during this time. If you eat it hot from the oven, the sauce will be very watery and later on, the leftover fruit part of the crumble will be gloopy rather than the saucy.

Store at room temperature for 1 day or refrigerate for up to 3.