Grease the slow cooker. You can use butter, non-stick spray, or even line it with a slow cooker liner.

Combine the cake mix, 1 ¼ cup of the milk, eggs, and oil in a mixing bowl. Whisk well until the cake batter is smooth and free of lumps.

Pour the cake batter into the prepared slow cooker.

Combine the remaining milk with the pudding mix in a medium mixing bowl. Whisk until smooth and creamy.

Pour that pudding mix directly into the center of the cake batter in the cooker. DO NOT MIX.

Cover and cook on low for 3 hours or until the sides of the cake become spongy.

Serve the cake while hot by spooning some of the cake as well as the pudding lava into a bowl and topping it with a scoop of vanilla ice cream.