Lightly grease the inside of a 3-quart slow cooker with non-stick cooking spray, butter, or oil.

Add all ingredients except for garnishes and whisk to combine.

Turn slow cooker on and cook on low power for 4-6 hours, or until pudding is golden brown on top, the inside has set and the internal temperature reaches 160°F.

To prepare like the photos in this post:

Use a spoon to lightly scrape the fully cooked portion of the pudding to the side (or scoop it into a bowl for eating later!). Fill dessert glasses or ramekins 3/4 full with pudding. Use the back of a spoon to smooth the tops. Instead of individual serving glasses, you could also spoon entire contents of pudding from the slow cooker into a 1 quart serving dish.

Arrange marshmallows on top of pudding. Use a kitchen torch to toast the marshmallows until brown (or place the dishes on a sheet pan under the broiler of your oven for 1-2 minutes, but watch them carefully so that they don't burn.

Allow marshmallows to cool slightly, then drizzle chocolate fudge sauce over the tops of the marshmallows. Serve immediately.