Preheat the oven to 350 degrees. Grease a 9 inch square or 11 x 7 inch rectangular baking pan.
Place the cherries in the baking dish and toss with sugar, flour, vanilla, and citrus juice, if using.
In another bowl, stir together the flour, brown sugar, oats, almonds, and salt. Pour the melted butter over top and stir until all the dry ingredients are moistened.
Use your fingers to pinch together the crumble to form various sized crumbles. Sprinkle them evenly over the fruit filling.
Place the crumble in the oven and bake for 40-45 minutes, or until the crumble is browned and bubbly. Check the crumble at 35 minutes. If the crumble is already well browned, loosely cover it with foil for the remaining bake time. Serve the crumble warm with ice cream, if desired.