Whisk together flour, baking powder and salt in a large bowl. Cut in the butter until crumbs form. Pour in the milk and stir into a dough. Cover and refrigerate until firm, about 10 minutes.
Make the filling:
Add all filling ingredients to a 4-5 quart slow cooker and carefully toss.
Whisk together the ingredients for the cinnamon sugar. Roll the chilled biscuit dough into small balls and toss them in the cinnamon sugar. Arrange on top of the filling and cook on HIGH for 2.5 hours, or until the filling is bubbly and a toothpick interred into the topping comes out clean.
Allow to rest for 15-20 minutes before serving, to allow the sauce to thicken.