Spray the insert of a slow cooker with nonstick cooking spray.
In a large mixing bowl, toss together all the frozen fruit, sugar and 1/2 cup baking mix. Transfer the fruit to the slow cooker. In another large mixing bowl, stir together 2 1/4 cups baking mix, 1/4 cup sugar, melted butter and milk with a wooden spoon. With your hands, drop bits of dough on top of the fruit in the slow cooker. In a small mixing bowl, stir together the remaining 1/4 cup sugar and ground cinnamon. Sprinkle the cinnamon sugar on top of the dough and place the lid on the slow cooker. Turn the power onto high and slow cook for 3 to 4 hours until the topping has puffed and the fruit is bubbling.
Serve warm with whipped cream or ice cream.