In a large bowl, combine the sliced plums, 1/3 cup of the granulated sugar, 1/4 cup of the flour, and the orange juice and toss well. Add the raspberries and toss lightly. Pour into a 9 by 12 by 2-inch baking dish.
For the topping, place the remaining 1 cup of flour, the remaining 1/3 cup of granulated sugar, the brown sugar, and the salt in the bowl of a food processor fitted with a steel blade and pulse a few times to combine. Add the butter and pulse until the butter is the size of peas. Pour the mixture into a bowl, add the oats, and work it with your hands until it's in large crumbles. Add 1/2 cup of the almonds and mix well.
Spread the topping evenly over the plums, making sure the fruit is covered. Sprinkle with some extra almonds. Bake for 40 minutes, or until the fruit is tender and bubbly and the topping is golden brown. Serve warm or at room temperature.