For serving: chopped toasted pecansdried cranberries, chopped dried apricots, chocolate chips, peanut butter, or any other mix-ins you enjoy with pumpkin
Place all of the ingredients, except for the toppings, in the bottom of a 4-to-6-quart slow cooker and stir to combine: Steel cut oats, water, milk, pumpkin, maple syrup, flaxseed meal, vanilla, cinnamon, ginger, nutmeg, cloves, and salt.
Cover and cook on low for 7 hours (overnight) or on high for 3 1/2 to 4 hours, until the oats are soft but maintain a bit of chew. Remove cover and stir to evenly combine the ingredients, scraping the oats off the bottom and away from the sides. Enjoy warm with desired toppings.
This recipe as written is not ultra sweet, but can easily be adjusted. I recommend trying it with the 1/4 cup pure maple syrup only, then adding additional to individual servings as you like.
Know thy slow cooker! Every crock pot is a little different, so you may need to adjust your cooking time, depending upon how quickly yours tends to finish recipes. I also recommend using a programmable slow cooker like this one, so that if you don't check it right away, the oatmeal doesn't burn.
If cooking overnight, another option to make sure the edges of the oatmeal do not burn (readers with very powerful slow cookers might have this problem), you can prepare the oatmeal inside a large, heatproof casserole dish that fits inside your slow cooker. Place the dish inside the slow cooker, then pour water around the dish half way up the sides to create a water bath. I haven't tried the recipe this way, but know it has been successful for others who have used it to make my Slow Cooker Banana Bread Overnight Steel Cut Oats.
Overnight steel cut oats can be refrigerated for up to 1 week or frozen for up to 2 months. To reheat, top desired amount with a few tablespoons of water or milk, then warm in the microwave or in a small saucepan until hot. If the oatmeal is frozen, let thaw overnight in the refrigerator before reheating.