Cooking spray, olive oil, or coconut oil, for greasing the slow cooker
4 cups old-fashioned rolled oats
1 cup raw nuts and/or seeds such as almonds, walnuts, or pecans
1/4 cup packed brown sugar
1/2 teaspoon ground cinnamon
1/4 teaspoon kosher salt
1/2 cup olive oil or coconut oil
1/2 cup liquid sweetener, such as maple syrup, honey, or agave syrup
1 tablespoon vanilla extract
1/2 cup dried fruit, chopped if large (optional)