Generously coat the inside of a 6-quart Crockpot with nonstick cooking spray.
Add the steel-cut oats, water and salt. Spread the oats evenly across the bottom.
1 cup traditional steel-cut oats, 4 cups water, 1/2 tsp salt
In a small bowl, combine the pumpkin purée, brown sugar, cinnamon and nutmeg.
1 cup canned pumpkin purée, 1/4 cup light brown sugar, 1 tsp ground cinnamon, 1/4 tsp ground nutmeg
Spoon the pumpkin mixture into the center of the Crockpot. It will quickly spread across the surface on its own. Scatter the chocolate chunks over the pumpkin mixture. Do not stir.
1/3 cup semisweet chocolate chunks
Cover and cook on Low for approximately 7 hours, or until the steel-cut oats are tender.
Add the vanilla, then stir everything together, incorporating the pumpkin and melted chocolate throughout the oatmeal.
1 tsp vanilla extract
Let stand for 5–10 minutes to thicken slightly. Spoon into bowls and add milk or cream as desired.
milk or cream