Grease the bottom and sides of a 4- or 5-quart crock pot. Combine flour, 2/3 cup sugar, baking powder and salt in a large bowl. Add the butter until you have coarse crumbs. Stir in milk until moistened. Spoon into bottom of crockpot and spread out evenly. Place the diced apples over top in an even layer. In a medium bowl, whisk together the orange juice, honey, melted butter, 1/4 cup sugar and cinnamon. Pour over the apples. Place a clean kitchen towel over the opening of the crockpot, then place the lid on. (This will keep condensation from soaking into the cake.) Set on high and cook 2 - 3 hours until apples are tender. Serve warm with ice cream.