Spray the insert of a slow cooker with nonstick cooking spray.
FILLING: In a large mixing bowl, toss together frozen fruit, sugar and 1/2 cup baking mix. Transfer the fruit to the slow cooker.
TOPPING: 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.
Cook on HIGH and for 3-1/2 to 4 hours until the topping has puffed and the fruit is bubbling. Serve warm with whipped cream or ice cream.