Step 1

Spray a 5-quart slow cooker with baking spray.

Step 2

Whisk together sugar, flour, cocoa, baking powder, baking soda, and salt in a large mixing bowl until combined. Add oil, vanilla, eggs, and 1 cup of the milk; stir to combine. Stir in boiling water just until combined. Pour cake batter into prepared slow cooker.

Step 3

Whisk together pudding mix and remaining 2 cups milk in a medium bowl until smooth. Let stand until slightly thickened, about 5 minutes. Pour pudding in center of cake batter in the slow cooker. Sprinkle evenly with chocolate chips.

Step 4

Place lid on slow cooker, and cook on HIGH until cake is dry to the touch, about 2 hours and 30 minutes. Serve with ice cream.