Pumpkin Spice Slow-Cooker Oatmeal

Ingredients: 1 cup steel-cut oats 4 cups water or milk (or a combination of both) 1 cup pumpkin puree 1/4 cup maple syrup or brown sugar 1 teaspoon vanilla extract 2 teaspoons pumpkin pie spice (or a mix of cinnamon, nutmeg, ginger, and cloves) 1/4 teaspoon salt Optional toppings: chopped nuts, dried cranberries, pumpkin seeds, a dollop of yogurt, or a drizzle of maple syrup