Lightly spray the inside of your slow cooker with nonstick cooking spray to prevent sticking.

Pour both cans of sliced peaches with all their juice into the bottom of the slow cooker. Stir in the vanilla extract and cinnamon if using.

Sprinkle the dry yellow cake mix evenly over the peaches. Do not mix — leave the cake mix sitting on top.

Place the thin slices of butter all across the top of the dry cake mix, covering as much area as possible.

Cover and cook on: High: 2 to 2½ hours, or Low: 3½ to 4 hours.

Scoop into bowls while warm. Best served with cold vanilla ice cream — the contrast is amazing!