Lightly grease a slow cooker with the butter. Add the oats, milk, cider, apples, cranberries, maple syrup, vanilla, Brown Sugar Vanilla Breakfast Seasoning, cinnamon, salt, and water, and gently stir to combine. Cover and cook on low for 6-8 hours.
In the morning, stir the oats, then serve warm topped with walnuts, pistachios, apple slices, and cranberries. Drizzle with extra maple syrup if desired.
*make this completely vegan by using vegan butter, or cooking spray instead of regular butter.