Grease your slow cooker with non-stick cooking spray or line with a slow cooker liner.
Placed sliced apples in bottom of slow cooker.
In a small bowl, combine the white sugar, brown sugar, and 2 teaspoons cinnamon. Sprinkle mixture over apples. Lightly toss to coat.
In a medium bowl, combine cake mix and remaining 2 teaspoons of cinnamon.
Add in melted butter and mix until crumbly.
Sprinkle cake mixture evenly over apples.
Cook on high for 2-3 hours, or on low for 4-6 hours, until edges are set. Center will be slightly wet.
Serve immediately with vanilla ice cream or whipped cream, if desired.