Add the melted butter, diced apples, brown sugar, salt, and McCormick seasonings to the slow cooker and toss to coat the apples.
Pour the water over the apples and then pour the oats on top.
Set the slow cooker to low and cook overnight or for 8-10 hours.
In the morning, stir the oatmeal, and serve. You can top it with a sprinkle of McCormick Good Morning Seasoning, some extra brown sugar, walnuts, warm milk, or anything else you’d like!