Prepare the slow cooker liner with nonstick cooking spray.
Place the apples in the slow cooker.
Stir together the dry ingredients: both sugars, cornstarch, and cinnamon. Sprinkle over the apples and toss the apples until evenly coated.
In a large measuring cup, stir together the melted butter, lemon juice, and vanilla. Pour over the apples.
Cover the slow cooker and cook on high for 2 hours. Be careful not to overcook as the apples will look intact but fall apart upon stirring.
Stir gently prior to serving.