Toss apples with cinnamon, allspice, and nutmeg. Place in a lightly greased slow cooker. Combine milk, softened butter, sugar, eggs, vanilla and 1/2 cup of biscuit baking mix. Spoon over apples. Combine remaining biscuit baking mix and brown sugar; cut in chilled butter until crumbly. Sprinkle over mixture in slow cooker; do not srit. Cover and cook on low setting for 6 to 7 hours or until apples are tender. Serve with ice cream or whipped cream.