Position rack in center of oven and preheat to 350°F. Lightly grease an 8- by 8-inch glass baking dish with coconut oil.
In a large bowl, combine oats, walnuts, cinnamon, ground ginger, and salt. Mix in diced apples, applesauce, coconut milk, eggs, maple syrup, and vanilla. Stir in coconut oil until all ingredients are well combined.
Spread mixture into prepared baking dish and bake for 30 minutes or until set and light golden brown on top. Allow to cool in the baking dish for at least 5 minutes before slicing. Serve warm with optional garnishes, such as additional chopped walnuts.